Macromolecular Complex Including MLL3, Carabin and Calcineurin Regulates Cardiac Remodeling

BACKGROUND

Cardiac hypertrophy is an intermediate stage in the development of heart failure. The structural and functional processes occurring in cardiac hypertrophy include extensive gene reprogramming, which is dependent on epigenetic regulation and chromatin remodeling. However, the chromatin remodelers and their regulatory functions involved in the pathogenesis of cardiac hypertrophy are not well characterized.

METHODS

Protein interaction was determined by immunoprecipitation assay in primary cardiomyocytes and mouse cardiac samples subjected or not to transverse aortic constriction for 1 week. Chromatin immunoprecipitation and DNA sequencing (ChIP-seq) experiments were performed on the chromatin of adult mouse cardiomyocytes.

RESULTS

We report that the calcium-activated protein phosphatase CaN (calcineurin), its endogenous inhibitory protein carabin, the STK24 (STE20-like protein kinase 3), and the histone monomethyltransferase, MLL3 (mixed lineage leukemia 3) form altogether a macromolecular complex at the chromatin of cardiomyocytes. Under basal conditions, carabin prevents CaN activation while the serine/threonine kinase STK24 maintains MLL3 inactive via phosphorylation. After 1 week of transverse aortic constriction, both carabin and STK24 are released from the CaN-MLL3 complex leading to the activation of CaN, dephosphorylation of MLL3, and in turn, histone H3 lysine 4 monomethylation. Selective cardiac MLL3 knockdown mitigates hypertrophy, and chromatin immunoprecipitation and DNA sequencing analysis demonstrates that MLL3 is de novo recruited at the transcriptional start site of genes implicated in cardiomyopathy in stress conditions. We also show that CaN and MLL3 colocalize at chromatin and that CaN activates MLL3 histone methyl transferase activity at distal intergenic regions under hypertrophic conditions.

CONCLUSIONS

Our study reveals an unsuspected epigenetic mechanism of CaN that directly regulates MLL3 histone methyl transferase activity to promote cardiac remodeling.

Inhibition of EPAC1 signaling pathway alters atrial electrophysiology and prevents atrial fibrillation

Introduction: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with increased mortality and morbidity. The Exchange Protein directly Activated by cAMP (EPAC), has been implicated in pro-arrhythmic signaling pathways in the atria, but the underlying mechanisms remain unknown. Methods: In this study, we investigated the involvement of EPAC1 and EPAC2 isoforms in the genesis of AF in wild type (WT) mice and knockout (KO) mice for EPAC1 or EPAC2. We also employed EPAC pharmacological modulators to selectively activate EPAC proteins (8-CPT-AM; 10 μM), or inhibit either EPAC1 (AM-001; 20 μM) or EPAC2 (ESI-05; 25 μM). Transesophageal stimulation was used to characterize the induction of AF in vivo in mice. Optical mapping experiments were performed on isolated mouse atria and cellular electrophysiology was examined by whole-cell patch-clamp technique. Results: In wild type mice, we found 8-CPT-AM slightly increased AF susceptibility and that this was blocked by the EPAC1 inhibitor AM-001 but not the EPAC2 inhibitor ESI-05. Consistent with this, in EPAC1 KO mice, occurrence of AF was observed in 3/12 (vs. 4/10 WT littermates) and 4/10 in EPAC2 KO (vs. 5/10 WT littermates). In wild type animals, optical mapping experiments revealed that 8-CPT-AM perfusion increased action potential duration even in the presence of AM-001 or ESI-05. Interestingly, 8-CPT-AM perfusion decreased conduction velocity, an effect blunted by AM-001 but not ESI-05. Patch-clamp experiments demonstrated action potential prolongation after 8-CPT-AM perfusion in both wild type and EPAC1 KO mice and this effect was partially prevented by AM-001 in WT. Conclusion: Together, these results indicate that EPAC1 and EPAC2 signaling pathways differentially alter atrial electrophysiology but only the EPAC1 isoform is involved in the genesis of AF. Selective blockade of EPAC1 with AM-001 prevents AF in mice.

Incessant pericarditis following the second dose of SARS-CoV-2 mRNA vaccine successfully treated with anakinra: a case report

Background

The SARS-CoV-2 pandemic has led to the development of the first mRNA vaccines used in humans. These vaccines are well tolerated, safe, and highly effective; however, post-marketing surveillance is revealing potential rare adverse effects. We report a case of incessant pericarditis following administration of the second dose of mRNA-1273 SARS-CoV-2 vaccine, unresponsive to conventional therapy, and successfully treated with anakinra.

Case summary

A 30-year-old man presented to the Emergency Department for incessant pericarditis unresponsive to evacuative pericardiocentesis and conventional first-line anti-inflammatory therapy. Given the typical ‘inflammatory phenotype’ clinically characterized by fever, C-reactive protein (CRP) elevation, and leucocytosis, we decided, in agreement with the rheumatologist team, to avoid glucocorticoid and to administer anakinra. A sudden clinical and echocardiographic improvement was observed, with complete resolution of the symptoms and of the pericardial effusion; similarly, CRP values progressively decreased. The patient was discharged at home; no recurrences of pericarditis were described at clinical and instrumental follow-up made 3 months later.

Discussion

Several cases of pericarditis have been described in patients who received the COVID-19 vaccination, especially with the mRNA vaccine that can induce a non-adaptive immunity response against the viral spike protein, triggering cardiac damage for a molecular mimicry mechanism; however, defined pathogenesis of pericarditis associated with mRNA vaccine is still missing. The clinical scenario described is characterized by the typical ‘inflammatory phenotype’, triggered by a disproportionate and uncontrolled activation of the inflammasome based on an interleukin-1 (IL-1) overproduction. We administered anakinra, an IL-1 blocking drug, with a sharp clinical, echocardiographic and laboratoristic improvement. The complete response observed in this case suggests that vaccine-related pericarditis could be triggered by an auto-inflammatory pathway based on IL-1 overproduction. Further research is, therefore, warranted to determine the mechanisms by which the mRNA vaccine may cause pericarditis in order to choose the most targeted therapy.

Levosimendan for acute right heart failure in COVID-19: another arrow in our quiver?

OBJECTIVE

SARS-CoV-2 infection is associated with a higher risk of acute right heart failure (RHF) due to primary right ventricle (RV) dilation and systemic inflammatory response, which in turn lead to microvascular and cardiomyocytes dysfunction, local hypoxia and multi-organ failure. In this clinical setting, levosimendan could be a viable therapy thanks to its right-heart tropism and its additional pleiotropic properties.

CASE REPORT

We present the case of a 72 years-old man with positive nasopharyngeal swab for SARS-CoV-2 infection, mild pulmonary involvement and clinical signs of new-onset RHF. We started a 12-hour levosimendan cycle to improve RV performance and reduce cardiac filling pressures.

RESULTS

We obtained a net clinical benefit in terms of acute RHF-related signs and symptoms, progressive renal and liver function improvement and concomitant reduction of high-sensitivity C-Reactive Protein and Interleukin-6 (IL-6) levels.

CONCLUSIONS

Acute RHF during SARS-CoV-2 infection could be related to a convergent widespread systemic inflammatory response. Thanks to its anti-inflammatory and anti-remodeling properties, levosimendan might represent a viable therapy in this clinical setting, contributing to the dampening of the inflammatory response.

Transcatheter versus surgical aortic valve replacement in patients with aortic stenosis: characterization of molecular pathways before and after treatment

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

Recently, the transcatheter aortic valve replacement (TAVR) has reformed the management of Aortic Stenosis (AS), providing a valid therapeutic alternative to surgical aortic valve replacement (SAVR). Although optimizing the timing of surgery is a crucial aspiration, the introduction of innovative pharmacological therapies able to modify disease evolution might help clinicians to treat patients in a non-invasive way. Several evidences pointed out the role of inflammation, oxidative stress, and pathological remodelling in AS natural history.

Purpose

The aim of this study is to assess biological pathways modifications after aortic valve replacement, comparing the transcatheter and the surgical approach.

Methods

We enrolled a total of 35 consecutive patients with severe symptomatic aortic stenosis undergoing aortic valve replacement with transcatheter (n = 19) or surgical (n = 16) approach. Biological samples were collected and stored before (T0) and 72 hours after the procedure (T1). We firstly performed gene expression arrays for a total of 132 genes, on two groups of pooled cDNA from peripheral blood mononuclear cells of TAVR (n = 10) and SAVR (n = 10) patients. Then, taking into account the most relevant result of the arrays, we selected 15 genes for validation.

Results

Our preliminary data showed several differences in the gene expression levels of the two groups under examination for a large number of molecules, mostly associated with the oxidative balance. More in detail, after procedure, TAVR patients showed higher levels of glutathione peroxidase 1 (GPX1, TAVR p = 0.029; SAVR p = 0.031) and glutathione reductase (GSR, p = 0.029), while SAVR patients showed higher expression of GPX1, catalase (CAT, p = 0.019) and NADPH oxidase 2 (NOX2, p = 0.008), thus confirming an intense post-operative oxidative stress particularly for patients undergoing surgery. Moreover, Caspase 3 (CASP3, p = 0.013), involved in apoptotic pathway and myocyte enhancer factor 2C (MEF2C, p = 0.036), implicated in overload induced hypertrophy genes showed a significantly reduction in their expression after TAVR.

Conclusions

In our study, we describe different gene expression signatures in patients with an AS diagnosis and their recalibration after AV replacement with two kinds of procedure, TAVR and SAVR. Our data describe for the first time an altered oxidative balance in patient undergoing aortic valve replacement, that is particularly evident for patients undergoing SAVR. A clearer understanding of biological processes taking place in the first hours post AV replacement lays the ground to a more efficient management of post-operative status and, in the incessant research for a tailored therapy, the results of our study add a little piece of information to assist clinicians in selecting the optimal procedure for each patient.

Takotsubo syndrome: a way to reach a straightforward diagnosis

Background/Introduction

Acute stress-induced cardiomyopathy, also known as Takotsubo Syndrome (TTS), was originally classified as a benign disease. Nowadays, this assumption has changed, especially in its long-term outcome, due to TTS clinical presentation, that often mirrors the acute myocardial infarction (MI) phenotype. Current knowledge already delineate clinical features distinctive of TTS and MI patients, however, diagnosis requires multiple, expansive, and invasive medical examinations. Moreover, concerning the biological panorama, very slight is known and the lack of a tailored therapy is resented. Therefore, a biological profile for this clinical category could provide easier and less invasive diagnostic tools, leading edge towards novel therapeutic pathways.

Purpose

The aim of the study is to perform a biological profile of the TTS group compared to the ST Segment Elevation Myocardial Infarction (STEMI) in order to explore the molecular peculiarities attendant the pathophysiologic mechanisms.

Methods

We performed a gene expression array on two groups of pooled cDNA from peripheral blood mononuclear cells, from TTS (n=11) and STEMI (n=19) patients. We conducted gene expression validations for each enrolled patient through qPCR.

Results

Our preliminary data displayed several differences in gene expression levels of a grand number of cell adhesion signaling molecule between the two groups. As shown in figure 1, three gene were more expressed in TTS group: Nitric Oxide Synthase 3, also known as endothelial NOS (NOS3; p=0.002), Superoxide dismutase 1 (SOD1; p=0.03) and transferrin receptor (TFRC; p=0.005). Meanwhile, five gene displayed a higher expression in STEMI patients compared to TTS: phospholipase A2 Group 7 (PLA2G7; p=0.04), Galectin 8 (LGALS8; p=0.02), Intercellular Adhesion Molecule 1 (ICAM1; p=0.002), Hyaluronidase 2 (HYAL2; p=0.01) and Hyaluronan Receptor (CD44; p=0.0002).

Conclusions

The earliest results of this study led us to focus on fewer genes related to endothelial and oxidative stress pathways. TTS is habitually triggered by intense emotional or physical stress. Indeed, our results showed how TTS patients present higher expression of NOS3, SOD1 and TFRC, all components involved in the oxidative stress pathways. In STEMI patients, top expressed genes, such as HYAL2, CD44 and ICAM1, are all associated with extracellular matrix turnover, likely due to the presence of a stenotic plaque and the consequent endothelial derangement. The uncovering of diagnostic biomarkers in TTS might improve the early, non-invasive, stratification of this group of patients, thus facilitating novel and personalized therapeutics design.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The present study was supported by the Italian National Project Grant PRIN 2017.

An unusual case of death using a compacting machine

In the large series of forensic injury, death from accidental me-chanical asphyxiation in adults is rare and is usually secondary to suffocation, aspiration, strangulation caused by entrapment of clothing in machinery (deaths at work) or asphyxiation in the course of erotic maneuvers. Compression asphyxia is a form of violent mechanical asphyxia in which the asphyxiated insult is produced by means of a compression and constriction mechanism of the thoracic cage. The authors report an unusual case of asphyxiated death from chest com-pression resulting from the action of a compacting machine, which occurred in a person who had fallen asleep in a waste bin.

Kv4 channel expression and kinetics in GABAergic and non-GABAergic rNST neurons

The rostral nucleus of the solitary tract (rNST) serves as the first central relay in the gustatory system. In addition to synaptic interactions, central processing is also influenced by the ion channel composition of individual neurons. For example, voltage-gated K⁺ channels such as outward K⁺ current (I_A) can modify the integrative properties of neurons. I_A currents are prevalent in rNST projection cells but are also found to a lesser extent in GABAergic interneurons. However, characterization of the kinetic properties of I_A, the molecular basis of these currents, as well as the consequences of I_A on spiking properties of identified rNST cells is lacking. Here, we show that I_A in rNST GABAergic (G+) and non-GABAergic (G-) neurons share a common molecular basis. In both cell types, there was a reduction in I_A following treatment with the specific Kv4 channel blocker AmmTx3. However, the kinetics of activation and inactivation of I_A in the two cell types were different with G- neurons having significantly more negative half-maximal activation and inactivation values. Likewise, under current clamp, G- cells had significantly longer delays to spike initiation in response to a depolarizing stimulus preceded by a hyperpolarizing prepulse. Computational modeling and dynamic clamp suggest that differences in the activation half-maximum may account for the differences in delay. We further observed evidence for a window current under both voltage clamp and current clamp protocols. We speculate that the location of Kv4.3 channels on dendrites, together with a window current for I_A at rest, serves to regulate excitatory afferent inputs.NEW & NOTEWORTHY Here, we demonstrate that the transient outward K⁺ current I_A occurs in both GABAergic and non-GABAergic neurons via Kv4.3 channels in the rostral (gustatory) solitary nucleus. Although found in both cell types, I_A is more prevalent in non-GABAergic cells; a larger conductance at more negative potentials leads to a greater impact on spike initiation compared with GABAergic neurons. An I_A window current further suggests that I_A can regulate excitatory afferent input to the nucleus.

Diabetes Remission and Relapse After Bariatric Surgery: a Nationwide Population-Based Study

PURPOSE

The long-term impact of bariatric surgery on the remission of type 2 diabetes (T2DM) remains to be clarified through large nationally representative cohorts. The objectives were to determine the incidence of T2DM remission and relapse after bariatric surgery, to determine the factors associated with remission and to establish a profile for patients at risk for relapse.

MATERIALS AND METHODS

We conducted a population-based cohort study using data from the French national health insurance database (Systeme national des données de santé [SNDS]). We had access to exhaustive regional data between 2013 and 2017 and to a national representative sample of the French population (EGB) from 2008 to 2018. Patients were included if they were adults and diabetics with incidental bariatric surgery.

RESULTS

This study shows that 50% of patients are in remission from diabetes after bariatric surgery within a median of 2 to 4 months. Diabetes relapse was observed in 13-20% within 10 years. The factors favouring remission already described were noted (non-insulin-dependent diabetes) and original factors were also identified, in particular the advantage of bypass surgery over sleeve gastrectomy, with more remissions and fewer relapses.

CONCLUSION

This study highlights a 50% prevalence of remission and a low prevalence of relapse. There are non-modifiable risk factors for remission and relapse (characteristics of diabetes, age, lipid-lowering therapy) and modifiable factors (type of surgery). Identifying these factors is essential for optimal management of patients. Additional data are essential to confirm the results of our analysis of the factors associated with relapse.

Bevacizumab as maintenance treatment in BRCA mutated patients with advanced ovarian cancer: A large, retrospective, multicenter case-control study

OBJECTIVE

The aim of this study was to investigate the correlation between BRCA mutational status and response to bevacizumab in a large advanced ovarian cancer (AOC) series.

METHODS

This is a multicenter, retrospective case-control study including upfront AOC treated between January 2015 and June 2019. The main inclusion criteria were: having received three weekly carboplatin-paclitaxel as first-line treatment, with or without Bevacizumab maintenance, knowledge of the BRCA mutational status.

RESULTS

Overall, 441 patients were included; 183 (41.5%) patients received bevacizumab (Cases), and 258 (58.5%) did not receive it (Controls). The BRCA mutated patients (BRCAmut) were 58 (39%) in the Cases group and 90 (34.9%) in the Controls group (p = .77). Patients who received bevacizumab had a significant 4-months increase in median progression free survival (mPFS: 21 vs. 17 months, p = .033). Concerning BRCAmut patients, no differences were shown between those who received bevacizumab or not in terms of mPFS (24 vs. 22 months, p = .3). Conversely, in BRCA wild-type (BRCAwt) population bevacizumab administration significantly prolonged mPFS (20 vs 15 months, p = .019). At multivariate analysis, independent factors of prolonged PFS were BRCA status (OR = 0.60), having received PDS (OR = 0.69), and complete cytoreduction (OR = 0.50), but not the bevacizumab administration (OR = 0.83, p = .22).

CONCLUSIONS

No evidence of oncological benefit in terms of PFS and OS related to bevacizumab maintenance therapy was found in BRCAmut patients. Differently, BRCAwt patients seem to benefit from antiangiogenic treatment in terms of mPFS.

Salvage lymphadenectomy in recurrent ovarian cancer patients: Analysis of clinical outcome and BRCA1/2 gene mutational status

OBJECTIVE

This study is aimed to analyze the clinical outcome of recurrent ovarian cancer patients bearing isolated lymph-node recurrence (ILNR) who underwent salvage lymphadenectomy (SL). The prognostic role of clinicopathological variables and the mutational status of BRCA1/2 have also been investigated.

METHODS

This retrospective, single-institutional study included women with platinum-sensitive lymph node recurrence underwent to SL between June 2008 and June 2018. Univariate and multivariate analysis was performed to evaluate the impact of clinical parameters, and BRCA1/2 mutational status on post salvage lymphadenectomy progression-free survival (PSL-PFS).

RESULTS

As of June 2019, the median follow-up after SL was 30 months, and the relapse has been documented in 48 (56.5%) patients. In the whole series, the median PSL-PFS was 21 months, and the 3-year PSL-PFS was 36.7%. The median PSL-PFS, according to patients with ILNR (N = 71) versus patients with lymph-nodes and other sites of disease (N = 14), was 27 months versus 12 months, respectively. Univariate analysis of variables conditioning PSL-PFS showed that platinum-free interval (PFI) ≥12 months, normal Ca125 serum levels, and number of metastatic lymph-nodes ≤3 played a statistically significant favorable role. In multivariate analysis, PFI duration ≥12 months and the number of metastatic lymph nodes ≤3 were shown to keep their favorable, independent prognostic value on PSL-PFS.

CONCLUSIONS

In the context of SL, the patients with long PFI and low metastatic lymph node numbers at ILNR diagnosis have the best outcome. The BRCA mutational status seems not associated with clinical variables and PSL-PFS, differently from other sites of disease in ROC patients.

Carboplatin-paclitaxel compared to Carboplatin-Paclitaxel-Bevacizumab in advanced or recurrent endometrial cancer: MITO END-2 - A randomized phase II trial

OBJECTIVE

Increased Vascular Endothelial Growth Factor Receptor (VEGF) expression in endometrial cancer (EC) is associated with a poor prognosis. Preliminary clinical data reported Bevacizumab effectiveness in EC both as single agent and in combination with chemotherapy.

METHODS

In a phase II trial, patients with advanced (FIGO stage III-IV) or recurrent EC were randomized to receive Carboplatin-Paclitaxel standard dose for 6-8 cycles vs Carboplatin-Paclitaxel and Bevacizumab 15 mg/kg in combination with chemotherapy and maintenance until disease progression or unacceptable toxicity. The primary endpoint was progression free survival (PFS).

RESULTS

108 patients were randomized; PFS (10.5 vs 13.7 months, HR 0.84 p = 0.43), overall response rate (ORR 53.1% vs 74.4%) and overall survival (OS) (29.7 vs 40.0 months, HR 0.71 p = 0.24) resulted in a non-significant increase in Bevacizumab treated patients. The PFS increase became significant when an exploratory analysis with the Breslow test was used. Moreover, patients treated with Bevacizumab experienced a significant increase in 6-month disease control rate (70.4% vs 90.7%). Cardiovascular events were more frequent in the experimental arm ("de novo" grade ≥2 hypertension 21% vs 0% and grade ≥2 thromboembolic events 11% vs 2% in the Bevacizumab vs standard treatment arm, respectively).

CONCLUSIONS

Bevacizumab combined with chemotherapy in the treatment of advanced/recurrent EC failed to demonstrate a significant increase in PFS in the MITO END-2 trial. Nevertheless, these preliminary data suggests some effectiveness of the antiangiogenic agent which merits further exploration in a larger population with a better molecular characterization.

Global lower limb muscle coactivation during walking at different speeds: Relationship between spatio-temporal, kinematic, kinetic, and energetic parameters

Muscle coactivation is the mechanism that regulates the simultaneous activity of antagonist muscles around the same joint. During walking, muscle joint coactivation varies within the gait cycle according to the functional role of the lower limb joints. In the present study, we used a time-varying multi-muscle coactivation function (TMCf) with the aim of investigating the coactivation of 12 lower limb muscles and its relationship with the gait cycle, gait speed (low, self-selected, and fast), ground reaction force, gait variability, and mechanical energy consumption, and recovery in a sample of 20 healthy subjects. Results show that the TMCf is speed dependent and highly repeatable within and between subjects, similar to the vertical force profile, and negatively correlated with energy recovery and positively correlated with both energy consumption and balance-related gait parameters. These findings suggest that the global lower limb coactivation behavior could be a useful measure of the motor control strategy, limb stiffness, postural stability, energy efficiency optimization, and several aspects in pathological conditions.

Collective and experimental research project for master's students on the pathophysiology of obesity

We describe here a collective and experimental research project-based learning (ERPBL) for master's students that can be used to illustrate some basic concepts on glucose/lipid homeostasis and renal function around a topical issue. The primary objective of this ERPBL was to strengthen students' knowledge and understanding of physiology and pathophysiology. The secondary objectives were to help students to develop technical/practical abilities and acquire transversal skills with real-world connections. Obesity is a worldwide public health problem that increases the risk for developing type 2 diabetes and nephropathies. To study the impact of western dietary habits, students evaluated the effects of a diet enriched with fat and cola [high-fat and cola diet (HFCD)] on metabolism and renal function in mice. Students mainly worked in tandem to prepare and perform experiments, but also collectively to compile, analyze, and discuss data. Students showed that HFCD-fed mice 1) developed obesity; 2) exhibited glucose homeostasis impairments associated to ectopic fat storage; and 3) displayed reduced glomerular filtration. The educational benefit of the program was estimated using three evaluation metrics: a conventional multicriteria assessment by teachers, a pre-/posttest, and a self-evaluation questionnaire. They showed that the current approach successfully strengthened scientific student knowledge and understanding of physiology/pathophysiology. In addition, it helped students develop new skills, such as technical and transversal skills. We concluded that this ERPBL dealing with the pathophysiology of obesity was strongly beneficial for master's students, thereby appearing as an efficient and performing educational tool.

Effect of Restraining the Base of Support on the Other Biomechanical Features in Patients with Cerebellar Ataxia

This study aimed to analyze the biomechanical consequences of reducing the base of support in patients with ataxia. Specifically, we evaluated the spatio-temporal parameters, upper- and lower-body kinematics, muscle co-activation, and energy recovery and expenditure. The gaits of 13 patients were recorded using a motion analysis system in unperturbed and perturbed walking conditions. In the latter condition, patients had to walk using the same step width and speed of healthy controls. The perturbed walking condition featured reduced gait speed, step length, hip and knee range of motion, and energy recovery and increased double support duration, gait variability, trunk oscillation, and ankle joint muscle co-activation. Narrowing the base of support increased gait instability (e.g., gait variability and trunk oscillations) and induced patients to further use alternative compensatory mechanisms to maintain dynamic balance at the expense of a reduced ability to recover mechanical energy. A widened step width gait is a global strategy employed by patients to increase dynamic stability, reduce the need for further compensatory mechanisms, and thus recover mechanical energy. Our findings suggest that rehabilitative treatment should more specifically focus on step width training.

Multifunctional Mitochondrial Epac1 Controls Myocardial Cell Death

Rationale:

Although the second messenger cyclic AMP (cAMP) is physiologically beneficial in the heart, it largely contributes to cardiac disease progression when dysregulated. Current evidence suggests that cAMP is produced within mitochondria. However, mitochondrial cAMP signaling and its involvement in cardiac pathophysiology are far from being understood.

Objective:

To investigate the role of MitEpac1 (mitochondrial exchange protein directly activated by cAMP 1) in ischemia/reperfusion injury.

Methods and Results:

We show that Epac1 (exchange protein directly activated by cAMP 1) genetic ablation ( Epac1 −/− ) protects against experimental myocardial ischemia/reperfusion injury with reduced infarct size and cardiomyocyte apoptosis. As observed in vivo, Epac1 inhibition prevents hypoxia/reoxygenation–induced adult cardiomyocyte apoptosis. Interestingly, a deleted form of Epac1 in its mitochondrial-targeting sequence protects against hypoxia/reoxygenation–induced cell death. Mechanistically, Epac1 favors Ca 2+ exchange between the endoplasmic reticulum and the mitochondrion, by increasing interaction with a macromolecular complex composed of the VDAC1 (voltage-dependent anion channel 1), the GRP75 (chaperone glucose-regulated protein 75), and the IP3R1 (inositol-1,4,5-triphosphate receptor 1), leading to mitochondrial Ca 2+ overload and opening of the mitochondrial permeability transition pore. In addition, our findings demonstrate that MitEpac1 inhibits isocitrate dehydrogenase 2 via the mitochondrial recruitment of CaMKII (Ca 2+ /calmodulin-dependent protein kinase II), which decreases nicotinamide adenine dinucleotide phosphate hydrogen synthesis, thereby, reducing the antioxidant capabilities of the cardiomyocyte.

Conclusions:

Our results reveal the existence, within mitochondria, of different cAMP–Epac1 microdomains that control myocardial cell death. In addition, our findings suggest Epac1 as a promising target for the treatment of ischemia-induced myocardial damage.

Diagnostic accuracy of MDCT in the evaluation of patients with peritoneal carcinomatosis from ovarian cancer: is delayed enhanced phase really effective?

OBJECTIVE

To assess the diagnostic accuracy of delayed enhanced phase in addition to portal enhanced phase in MDCT imaging for depicting peritoneal carcinomatosis (PC) implants in patients with ovarian cancer.

PATIENTS AND METHODS

We retrospectively reviewed double-phase, portal enhanced phase (PEP) and delayed enhanced phase (DEP), MDCT-examinations of 40 patients with clinical suspicion of recurrent PC from histopathologically-proven ovarian cancer, previously treated with both cytoreductive surgery and adjuvant/neoadjuvant chemotherapy. Image assessment was performed by three independent blinded readers (2 experienced and 1 less-experienced radiologists) in 3 different reading sessions: PEP (set A), DEP (set B), and PVP + DEP (set C). All CT-images were qualitatively assessed on the basis of the location of the lesion (based on Sugarbaker scheme), presence (indicating a confidence level for the diagnosis of PC), size and pattern. Reference standard both for detection and exclusion of PC was the evaluation of double-phase MDCT exams performed by two experienced readers in consensus, knowing clinical and laboratoristic parameters as well as previous and subsequent imaging (follow-up minimum of 12 months). Sensitivity, specificity, PPV, NPV and diagnostic accuracy of each reader for each reading session were calculated and compared. A subgroup analysis based on lesion pattern was also performed.

RESULTS

On a total of 507 abdominal-pelvic sites evaluated, PC was found in 182 regions (35.9%). When considering experienced radiologists, no statistically significant differences (p>0.05) were found between the different sets of images. The analysis by less-experienced radiologist showed lower statistical results, which significantly improved when both PEP and DEP were evaluated. In the subgroup analysis, DEP showed significantly higher statistical results in the case of micronodular patterns.

CONCLUSIONS

Our results indicate that the CT-acquisition protocol in patients with ovarian cancer for tumor staging should be based on portal phase alone, with a significant radiation dose reduction, whereas the addition of delayed phase images is useful for less-experienced readers.

Cyclic AMP Sensor EPAC Proteins and Their Role in Cardiovascular Function and Disease

cAMP is a universal second messenger that plays central roles in cardiovascular regulation influencing gene expression, cell morphology, and function. A crucial step toward a better understanding of cAMP signaling came 18 years ago with the discovery of the exchange protein directly activated by cAMP (EPAC). The 2 EPAC isoforms, EPAC1 and EPAC2, are guanine-nucleotide exchange factors for the Ras-like GTPases, Rap1 and Rap2, which they activate independently of the classical effector of cAMP, protein kinase A. With the development of EPAC pharmacological modulators, many reports in the literature have demonstrated the critical role of EPAC in the regulation of various cAMP-dependent cardiovascular functions, such as calcium handling and vascular tone. EPAC proteins are coupled to a multitude of effectors into distinct subcellular compartments because of their multidomain architecture. These novel cAMP sensors are not only at the crossroads of different physiological processes but also may represent attractive therapeutic targets for the treatment of several cardiovascular disorders, including cardiac arrhythmia and heart failure.

Clinical predictors of fever in stroke patients: relevance of nasogastric tube

OBJECTIVES

Fever frequently occurs in stroke patients and worsens their prognosis. However, only few studies have assessed the determinants of fever in acute stroke, and no study has specifically addressed the possible prediction of the development of fever.

MATERIALS AND METHODS

This investigation included 536 patients with acute stroke and a body temperature <=37°C during the first 24 h of stay. Ninety-two of them (17.2%) subsequently developed fever (defined as a temperature >=37.5°C starting after 24 h). Among the clinical variables available during the first 24 h from admission, those predictive of the subsequent appearance of fever were searched for. One hundred further patients had a temperature >37°C during the first 24 h.

RESULTS

In univariate analysis, many variables were predictive of the subsequent development of fever, but in multivariate analysis, only the following four predictors remained significant (odds ratio [95% confidence interval], P value): nasogastric tube (4.0 [2.2-7.4], <0.0001), atrial fibrillation (2.3 [1.4-3.8], 0.001), total anterior circulation syndrome (2.0 [1.2-3.5], 0.01), and urinary catheter (1.9 [1.1-3.3], 0.01). Among the 52 (9.7%) patients with three or four predictors, 31 (59.6%) subsequently developed fever. In addition, the factors independently associated with a temperature >37°C during the first 24 h were as follows: National Institutes of Health Stroke Scale (P < 0.0001), hemorrhagic stroke (P = 0.0008), atrial fibrillation (P = 0.002), and total parenteral nutrition (P = 0.03).

CONCLUSIONS

In patients with acute stroke, four clinical variables were found to be independently associated with the risk of developing fever and, of them, nasogastric tube was the strongest and most significant one.

Locomotor patterns in cerebellar ataxia

Several studies have demonstrated how cerebellar ataxia (CA) affects gait, resulting in deficits in multijoint coordination and stability. Nevertheless, how lesions of cerebellum influence the locomotor muscle pattern generation is still unclear. To better understand the effects of CA on locomotor output, here we investigated the idiosyncratic features of the spatiotemporal structure of leg muscle activity and impairments in the biomechanics of CA gait. To this end, we recorded the electromyographic (EMG) activity of 12 unilateral lower limb muscles and analyzed kinematic and kinetic parameters of 19 ataxic patients and 20 age-matched healthy subjects during overground walking. Neuromuscular control of gait in CA was characterized by a considerable widening of EMG bursts and significant temporal shifts in the center of activity due to overall enhanced muscle activation between late swing and mid-stance. Patients also demonstrated significant changes in the intersegmental coordination, an abnormal transient in the vertical ground reaction force and instability of limb loading at heel strike. The observed abnormalities in EMG patterns and foot loading correlated with the severity of pathology [International Cooperative Ataxia Rating Scale (ICARS), a clinical ataxia scale] and the changes in the biomechanical output. The findings provide new insights into the physiological role of cerebellum in optimizing the duration of muscle activity bursts and the control of appropriate foot loading during locomotion.

Molecular mechanism underlying the cerebral effect of Gly-Pro-Glu tripeptide bound to L-dopa in a Parkinson's animal model

Oxidative stress is a critical contributing factor to neurodegenerative disorders. Therefore, the inhibition of ROS formation, responsible for chronic detrimental neuroinflammation, is an important strategy for preventing the neurodegenerative disease and for neuroprotective therapy. Gly-Pro-Glu (GPE) is the N-terminal tripeptide of insulin-like growth factor-I, which is naturally cleaved in the plasma and brain tissues. GPE has neuroprotective effects since it crosses the blood-CSF and the functional CSF-brain barriers and binds to glial cells. It has been shown that GPE improves motor behaviour in rats after 6-OHDA lesion, although it does not rescue dopaminergic neurons. Thus, we hypothesized that the GPE therapeutic efficacy in a Parkinson model might be improved by combining GPE to L: -dopa. Here, we used an animal model that represents a progressive chronic Parkinson's disease (PD) model, characterized by high levels of oxidative stress and inflammation. We showed that the co-drug, in which L: -dopa is covalently linked to the GPE tripeptide, by down-regulating the expression of inflammatory genes, decreases the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced inflammatory response and, by up-regulating tyrosine hydroxylase, reduces MPTP-induced neurotoxicity. Furthermore, by determining the nuclear translocation/activation of Nrf2 and NF-κB, we showed that systemic administration of the co-drug activates Nrf2-induced antioxidant response while suppressing NF-κB inflammatory pathway. Data suggest that the binding of L: -dopa to GPE tripeptide might represent a promising strategy to supply L: -dopa to parkinsonian patients.

Seeking sense of antisense switch transcripts

In B lymphocytes, class switch recombination (CSR) machinery targets highly repetitive sequences, called switch (S) sequences, in the constant domain of the immunoglobulin heavy chain (IgH) locus. Cotranscriptional generation of R loops at S sequences provides the substrate for the mutagenic enzyme AID (Activation-Induced cytidine Deaminase), which initiates the DNA breaks at the transcribed sequences. Both sense and antisense transcripts across the S regions have been reported. Our recent work shows that, unlike its sense counterpart, antisense transcription of S sequences is dispensable for CSR in vivo.

[Walking efficiency of blind people on trapezoidal and sinusoidal section tactile leading indicators]

Gait of visually impaired subjects (VIS) is worse than that of sighted ones. VIS can use tactile ground surface indicators to optimize their walking efficiency. Aim of the study was to compare VIS walking efficiency on either trapezoidal and sinusoidal shape leading indicators. VIS walking on the sinusoidal leading indicators showed a worsening of the time-distance parameters (a longer stance phase, a shorter swing phase and shorter step and stride lengths), reduced lower limb joint excursions and increased center of mass oscillations. In conclusion sinusoidal tactile indicators induce a stiffening of joints and a loss of balance with an increased risk of fall.

Walking strategies of visually impaired people on trapezoidal- and sinusoidal-section tactile groundsurface indicators

The visual system in walking serves to perceive feedback or feed-forward signals. Therefore, visually impaired persons (VIP) have biased motor control mechanisms. The use of leading indicators (LIs) and long canes helps to improve their walking efficiency. The aims of this study were to compare the walking efficiency of VIP on trapezoidal- and sinusoidal-section LIs using an optoelectronic motion analysis system. VIP displayed a significantly longer stance phase, a shorter swing phase and shorter step and stride lengths when they walked on the sinusoidal LI than when they walked on the trapezoidal LI. Compared with the trapezoidal LI, VIP walking on the sinusoidal LI displayed significantly lower joint ranges of motion. The centre of mass lateral displacement was wider for VIP walking on the sinusoidal LI than on the trapezoidal LI. Some significant differences were also found in sighted persons walking on both LIs. In conclusion, the trapezoidal shape enabled visually impaired subjects to walk more efficiently, whereas the sinusoidal shape caused dynamic balance problems. STATEMENT OF RELEVANCE: These findings suggest that VIP can walk more efficiently, with a lower risk of falls, on trapezoidal-section than on sinusoidal-section LIs. These results should be considered when choosing the most appropriate ground tactile surface indicators for widespread use.

Abstract P2-10-05: Referral to Genetic Services (GS) and Mutation Yield in 1132 Individuals at Risk for Hereditary Breast Ovarian Cancer Syndromes (HBOC)

Background: Family history directs referral of unaffected individuals to GS and is the main strategy to identify hereditary breast ovarian cancer syndrome. In unaffected individuals with known familial mutations, potentially life saving information can be provided to a large number of these individuals at a very modest cost.

Objectives: 1) To determine the rate of deleterious mutations in high risk individuals, based on pedigree, and 2) to identify the origin of their referral. Methods:

Over a 5-year period (2004 -2009) we analyzed the source of referral for genetic testing and the mutations detected in 1132 consecutively tested individuals. Of 1132 patients tested for BRCA1 or BRCA2 mutations, 420 were unaffected by cancer and 712 had breast or ovarian cancer at the time consultation. We excluded those from families who were previously tested at our institution to limit the bias for mutation positivity.

Results:

Seven hundred and sixty five patients were tested via comprehensive BRCA analysis (63 patients also had BART analysis) and of those only 7% (55) had deleterious mutations. Only 3% (24) had mutations in BRCA1 gene, and 29 patients had deleterious mutations in BRCA2. Of the 63 patients who underwent BART only 3% (2) had large deletions in BRCA1 gene. Two hundred and seventy three patients were tested for the three known Ashkenazi mutations and 20% (57) had deleterious mutations 10% (28) in BRCA1 gene and 10% (29) in BRCA 2. Ninety four patients were tested for known family mutations with single site analysis and there were (57%) 54 had deleterious mutations 27% (26) in BRCA 1 gene and 29% (28) in BRCA 2. Referring source was: self 283 (25%), GYN 430 (38%), surgeon 283 (25%), PCP 136 (12%) cases. Conclusions:

Single site testing of a known mutation costs ∼ 400$ and in 94 patients (8%) gave rapid information about cancer risk. Of these 27% (26) unaffected individuals were identified as carrying deleterious mutations and 73% (68) individuals found out their cancer risk was average. The yield of testing by comprehensive BRCA analysis was 7%, M3 panel detected 20% deleterious mutation and single site analysis for known familial mutations had the lower cost and higher yield of 57%. Primary care physicians identified only 12% of patients with high risk for hereditary cancer syndromes.

Discussion:

Although family history is the cornerstone of high-risk patient referral to GS, primary care physicians referred only 12% of all patients at risk for HBOC. Attention to family history and increased public awareness of hereditary risk are effective means of identifying at risk populations for referral for GS. The yield of mutation detection is highest and cost effective in families with known mutations. Our yield of 57% detection in families with known mutations is likely an indication that not all family members at risk seek genetic counseling or are referred at the same center.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-10-05.

Optimizing Burn Treatment in Developing Low-and Middle-Income Countries with Limited Health Care Resources (Part 2)

The present review of the literature aims at analysing the challenges facing burn management in low- and middleincome countries (LMICs) and exploring probable modalities to optimize burn management in these countries. In Part 1, the epidemiology of burn injuries and the formidable challenges for proper management due to limited resources and inaccessibility to sophisticated skills and technologies in LMICs were presented. Part II will discuss the actual state of burn injuries management in LMICs.

Optimizing burn treatment in developing low- and middle-income countries with limited health care resources (part 1)

In developing countries burn injuries are much more common than in the USA and Europe or other affluent developed countries, due to poverty, overcrowding, and illiteracy, and are associated with higher mortality rates. The high incidence makes burns an endemic health hazard in these countries. Over 90% of burn-related fatalities occur in developing or low- and middle-income countries (LMICs), with south-east Asia alone accounting for over half of fire-related deaths. Management of burns and their sequelae even in the well-equipped, modern burn units of advanced affluent societies remains demanding despite advances in surgical techniques and development of tissue-engineered biomaterials available to these burn centres. Undoubtedly, in a developing country with limited resources and inaccessibility to sophisticated skills and technologies, management of burns constitutes a major challenge. The present review of the literature analyses the challenges facing burn management in LMICs and explores probable modalities to optimize burn management in these countries. The review will be published in three parts. Part I will present the epidemiology of burn injuries and challenges for management in LMICs. Part II will be about management of burn injuries in LMICs and Part III will discuss strategies for proper prevention and burn care in LMICs.

[Understanding the different functions of vitamin D]

Exposure of the skin to sunlight is now considered the most important source of vitamin D in Western countries. It is presumed to contribute approximately two thirds of the total requirement, leaving the remaining one third to the few foods naturally rich in this vitamin. In the skin, vitamin D is synthesized as a cholesterol chain which undergoes structural modifications following exposure to UVB rays. Once produced in the skin or absorbed in the gut as cholecalciferol, vitamin D enters the blood to be transported by a specific vitamin D binding protein, which is synthesized in the liver and has a powerful buffering capacity. The transport system carries the metabolites to the sites of further activation (25-hydroxylation in the liver and 1alpha-hydroxylation in the kidney), ultimately resulting in the production of calcitriol. This last compound, now regarded as a hormone, circulates freely in minimal amounts and, compared with the other metabolites, shows the highest affinity for the vitamin D receptor (VDR). The mechanism of VDR activation is rather complex, resulting in either stimulation or inhibition of protein synthesis. Importantly, besides its presence in parathyroid, bone, kidney and intestine, this receptor has been demonstrated in several tissues, where its stimulation results in a reduced proliferation rate and increased differentiation. Accordingly, vitamin D is now regarded as a complex hormonal system, involved not only in the regulation of divalent ions and bone, but also in the proliferation and differentiation of numerous cell types with potential involvement in several diseases like cancer, immune diseases, diabetes, hypertension and heart failure.

Fibroblast growth factor 1 induced during myogenesis by a transcription-translation coupling mechanism

Fibroblast growth factor 1 (FGF1) is involved in muscle development and regeneration. The FGF1 gene contains four tissue-specific promoters allowing synthesis of four transcripts with distinct leader regions. Two of these transcripts contain internal ribosome entry sites (IRESs), which are RNA elements allowing mRNA translation to occur in conditions of blockade of the classical cap-dependent mechanism. Here, we investigated the function and the regulation of FGF1 during muscle differentiation and regeneration. Our data show that FGF1 protein expression is induced in differentiating myoblasts and regenerating mouse muscle, whereas siRNA knock-down demonstrated FGF1 requirement for myoblast differentiation. FGF1 induction occurred at both transcriptional and translational levels, involving specific activation of both promoter A and IRES A, whereas global cap-dependent translation was inhibited. Furthermore, we identified, in the FGF1 promoter A distal region, a cis-acting element able to activate the IRES A-driven translation. These data revealed a mechanism of molecular coupling of mRNA transcription and translation, involving a unique process of IRES activation by a promoter element. The crucial role of FGF1 in myoblast differentiation provides physiological relevance to this novel mechanism. This finding also provides a new insight into the molecular mechanisms linking different levels of gene expression regulation.

Concentrations of cytokines IL-6 and IL-10 in plasma of burn patients: their relationship to sepsis and outcome

Burn injury induces a suppression of the Th1 response, which is associated with an increased susceptibility to conditions of infection, morbidity, and mortality. It is well established that cytokines modulate the pathogenesis of burn injury. In this study, plasma levels of interleukin-6 (IL-6) and interleukin-10 (IL-10) were determined in burn patients and correlated with the severity of sepsis. Sixty adult burn patients (total body surface area burned, 8-80%) were included in the study, of whom 34 developed sepsis and 14 died. The nonseptic group consisted of 26 patients. Thirty-one healthy blood donors served as controls. Patients were not treated with antibiotics until sepsis occurred. Plasma samples were collected immediately post-burn and after several days, and cytokine concentrations were determined by ELISA. Within three days, all the patients presented high levels of circulating IL-6, which were significantly higher in septic patients than in nonseptic patients (349 ± 278 vs 63 ± 56 pg/ml, p < 0.001).IL-10 levels were higher in septic patients than in nonseptic patients at all times in our study. The value of 60 pg/ml shows a sensitivity of 92% and a specificity of 93% in the differentiation of survivor from nonsurvivor septic patients. In this study the high value of circulating IL-10 on day 3 suggests that cytokine may discriminate between nonsurvivor septic and survivor septic patients.