Aortic valve calcium score: does it correlate with mean transaortic gradient?

Introduction

Aortic valvular calcium score (AVCS) is useful in patients with aortic stenosis for whom echocardiography was not conclusive in grading its severity. Transcatheter aortic valve implantation (TAVI) is an established procedure of treatment in symptomatic severe AS. The burden of aortic valve calcification has been associated with some TAVI related complications (as perivalvular leaks), but at the same time it is well accepted that some degree of calcification is needed to ensure stable anchoring of the prosthesis to the aortic annulus.

Purpose

To assess if there is a correlation between aortic valve calcium score and mean transvalvular gradient 6 months after TAVI – is a higher AVCS correlated with lower mean transaortic gradient after TAVI?

Methods

We performed a single-center, retrospective cohort study including patients who underwent TAVI with a preoperative standardized contrast enhanced MSCT with AVCS available. Clinical and echocardiographic data were collected previously to TAVI (pre-TAVI) and at 6 months follow up (6M-FUP).

Results

A total of 187 patients were included, with 54% female and a mean age of 79.4±9.0 years old. Most patients had tricuspid aortic valve (95.7%); 5 patients had aortic bicuspidy and 3 had aortic valve bioprothesis. Concerning the valve type, 73.3% had new generation prosthesis and the main valve used was the CoreValve Evolut Pro (33.7%). Also, 38,5% needed balloon pre-dilation before TAVI. The mean pre-TAVI aortic transvalvular maximum and mean gradients were 76.5±23.2 mmHg and 48.3±15.5 mmHg, respectively; mean aortic valve area was 0.75±0.16 cm2. The mean AVCS was 2851±1524 AU (Agaston Units); 81.2% of women had AVCS>1300 AU and 74.4% men had AVCS >2000 AU. Comparing transvalvular aortic gradients previously and 6M-FUP after TAVI, there was an average differential of maximum gradient of 61±22 mmHg and of mean gradient of 40±15 mmHg. A negative and weak correlation was found between the AVCS and the maximum gradient (pearson coefficient of −0.181, p=0.02) and between mean gradient at 6M-FUP (pearson coefficient of −0.191, p=0.014).

Discussion and conclusion

AVCS is a significant predictor for death, stroke and perivalvular leaks after TAVI. On the other hand, high AVCS is associated with better seating in the native annulus during deployment. Nevertheless, high AVCS did not strongly correlated with mean transaortic gradient 6 months after TAVI.

Funding Acknowledgement

Type of funding sources: None.

Reduced 3D-left atrium ejection fraction predicts development of atrial fibrillation in patients with hypertrophic cardiomyopathy

Introduction

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), occurring in approximately 25% of patients, related to left atrial (LA) dilatation and remodeling. HCM patients who develop AF have increased risk of HCM-related death, functional impairment, and stroke. Accurate risk stratification for AF in this population is crucial as contemporary treatments are highly successful.

Purpose

To assess if new echocardiographic parameters can predict the development of AF in HCM patients.

Methods

HCM patients who underwent comprehensive echocardiographic examination during 2011 were followed and checked for “de novo” AF until November 2021. We searched for associations between AF development and novel echocardiographic parameters such as LA Volume index, Left Atrioventricular Coupling Index (LACI, as LAVI/a'), 3D LA volumes and 3D LA ejection fraction (3D-LAEF).

Results

A total of 43 patients were included, with 62.8% male and mean age 56,1±6,2 years old. 55.8% had the septal asymmetric HCM type and mean LV mass was 326±127g. Mean LA diameter and biplane 2D volume was 46±7 mm and 78±37 mL, respectively. 11.6% of patients already had AF. During a median follow-up of 9.4 years, the incidence of “de novo” AF was 31,6%. Within the total 17 patients with AF, 35,2% took warfarin and the remaining direct oral anti-coagulation. No stroke was documented. There were 3 deaths (mortality rate of 7,0%), none from cardiac causes.

No association was found between AF development and LAVI, LACI or 3D LA volumes. We only found a statistically significant difference regarding 3D-LAEF, which was lower in patients who developed AF compared with those without AF (26±12% VS 39±19%, p=0.04).

Binary logistic regression analysis found that reduced 3D-LAEF predicts the development of AF (p=0.019, odds ratio [OR] 2.6, 95% confidence interval [CI] 1.0 to 1.1). The area under a receiver operating characteristic curve using 3D-LAEF as a predictive marker for AF development in HCM patients was 0.743 (p=0.004). When the cut-off value of 3D-LAEF was set at 34,5%, the sensitivity and specificity for AF diagnosis were 66% and 86%, respectively.

Conclusion

In our study, 3D LAEF predicted the development of AF in HCM patients – this may be a useful tool to identify patients at high risk of future AF who may benefit from more intensive rhythm monitoring and a lower threshold for oral anticoagulation.

Funding Acknowledgement

Type of funding sources: None.

20 year-follow up of mitral stenosis patients after percutaneous valve commissurotomy: moderate disease of other valves as predictor for re-intervention

Background

Percutaneous valve commissurotomy (PMC) is a viable alternative to mitral valve (MV) surgery in the treatment of patients with clinically significant mitral stenosis (MS). About 40% of patients treated with PMC will require at least one reintervention (either PMC or MVS) along time.

Purpose

To evaluate the long-term results of PMC in patients with rheumatic MS.

Methods

We retrospectively analysed all consecutive patients between 1991 and 2008 with clinically significant rheumatic MS undergoing PMC. Clinical and echocardiographic data were collected at baseline and during early and long-term follow-up. MACE was a composite of adverse events defined as all-cause mortality, MV re-intervention or cardiovascular hospitalization.

Results

A total of 124 patients were enrolled: 108 (87%) were female, with a mean age at the time of PMC of 46±11 years.

At baseline, 34% patients were in NYHA class ≥ III and 81% had a Wilkins score ≤8; all patients had preserved biventricular systolic function and 83% presented pulmonary hypertension. Regarding associated valve disease, 46 patients had mild tricuspid regurgitation (TR), 19 mild aortic regurgitation (AR), 14 moderate IT and 5 moderated AR.

Most of the procedures were successful (91%) and without complications (94%), with median improvement in MV area of 0.9 cm2 (IQR 0.5) and median reductions in mean transmitral gradient (MTG) of 6 mmHg (IQR 6) and in pulmonary artery systolic pressure (PASP) of 8 mmHg (IQR 10) early after PMC.

During the mean follow-up of 20±6 years, 52 (42%) of patients had MV re-intervention (86% surgery and 14% re-PMC), 37 (30%) were hospitalized and 30 (24%) died. Concerning time-to-event analysis, approximately 80% of patients kept MACE-free after 10 years; after 30 years, more than 20% continued MACE-uneventful, approximately 50% were alive and about 45% were free from re-intervention.

Considering patients submitted to surgical re-intervention, 9 underwent MV valvuloplasty and the others MV replacement with mechanical (32) or biological prothesis (11). At the same procedure, 23 patients were submitted to tricuspid annuloplasty, 9 to other valve replacement and one to coronary artery bypass graft.

Using Cox regression, we found that the presence of moderate disease of other valves at PMC time was associated with a 2.3-fold greater rate of re-intervention compared to patients with none or mid disease of other valves (HRcrude 2.3; 95% IC 1.221–4.331, p=0.017). After adjusting for the success of the PMC and for mitral regurgitation after PMC, the observed effect remained significant (HRadjusted = 2.7; 95% CI 1.417–5.233, p=0.003).

Conclusion

PMC was safe and effective in clinically significant rheumatic MS. Most of the patients were free from adverse events after 10 years and half were alive after 30 years. Still, about 40% required re-intervention, with moderate disease of other valves as its independent predictor.

Funding Acknowledgement

Type of funding sources: None.

Aortic valve calcium score and peri-prothesis leaks after transcatheter aortic valve implantation: a hint?

Funding Acknowledgements

Type of funding sources: None.

Introduction

The first-line evaluation of aortic stenosis (AS) severity is Doppler echocardiography. Aortic valvular calcium score (AVCS) measured by tomography scans (TS) is useful in patients for whom echocardiography is not conclusive. For high-risk patients with symptomatic severe AS, transcatheter aortic valve implantation (TAVI) is an established procedure of treatment. The burden of aortic valve calcification has been associated with some TAVI related complications. Peri-prothesis leaks (PPL) are an important complication that may compromise TAVI net results and further refinements are required to predict high-risk patients.  Purpose: To access if there is an association between aortic valve calcium score and moderate to severe (mod-sev) peri-prothesis leaks immediately and 6 month after TAVI.  Methods: We performed a single-center, retrospective cohort study including patients who underwent TAVI with a preoperative standardised TS with AVCS available. Clinical and echocardiographic data were collected previously to TAVI (pre-TAVI) and at 6 months follow up (6M-FUP).  Results: A total of 187 patients were included, with 54% female and a mean age of 79.37± 9.029 year-old. Most patients had tricuspid aortic valve (95.7%); 5 patients had aortic bicuspidy and 3 had aortic valve bioprothesis. Considering left ventricular systolic function, the majority had conserved function (73.0%), the remaining had mild (9.7%), moderate (11.4%) or severe (5.9%) dysfunction.  Concerning the valve type, 73.3% had new generation prosthesis and the main valve used was the CoreValve Evolut Pro (33.7%). Also, 38.5% patients underwent balloon valve pre-dilation before implantation. In-hospital mortality was 2.7%. At 6M-FUP, 8 of 182 patients had dead.  The mean AVCS was 2851 ± 1524 AU (Agaston Units); 81.2% of women had AVCS > 1300 AU and 74.4% men had AVCS >2000 AU.  Comparing AVCS with the presence or absence of moderate to severe peri-prothesis leaks, no statistically significant difference was found immediately (no vs mod-sev leak, AS: 2758 ± 2308 vs 3621 ± 1376, p= 0,13) and 6 months after the procedure (no vs mod-sev leak, AS: 2892 ± 2366 vs 3621 ± 1424, p = 0.15). Considering earlier (Portico, CoreValve Evolut R) vs newer valves (CoreValve Evolut Pro; Edward Sapiens 3; Accurate Neo), there was no statistically significant difference relating AVCS and PPL; however, in patients who had newer valves there was a trend to higher AVCS and moderate to severe leaks, both on the immediate (no vs mod-sev leak, AS: 2777 ± 2507 vs 3601 ± 1385, p = 0.07) and at 6 months (no vs mod-sev leak, AS: 2782 ± 2506 vs 3984 ± 1138, p = 0.06). No statistically significant difference was found when comparing pre-ballooning dilatation. Conclusion: Aortic calcium measured by Agatston score did not show an association with new moderate to severe peri-valvular leaks after TAVI. Nevertheless, it seems to be a trend for higher AS and moderate to severe peri-prothesis leaks when newer valves are implanted.

Impact of severe mitral annular calcification on mitral regurgitation after transcatheter aortic valve implantation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Transcatheter aortic valve implantation (TAVI) has become the standard of care treatment in patients with severe aortic stenosis who are at intermediate or high risk for surgical aortic valve replacement. Mitral annular calcification (MAC) is frequent in patients with aortic stenosis, and its presence is associated with increased cardiovascular morbidity and mortality. Not infrequently, it is associated with significant morphologic and functional abnormalities of the mitral valve apparatus.

Purpose

 The aim of this work is to evaluate the relationship between severe MAC and the presence and development of significant mitral regurgitation after TAVI.

Methods

 We retrospectively analyzed all patients who underwent TAVI at a tertiary center from October 2014 to November 2019. Clinical, echocardiographic and procedure-related data were collected until a follow-up of 6 months. Statistical analysis was conducted on IBM SPSS® Statistics software. Descriptive statistics were calculated for all variables. Sample T-test, Chi-square and Wilcoxon sign test were used. A p-value < 0.05 was considered significant. The presence and severity of MAC was defined according to echocardiographic data. Severe MAC was defined by the presence of calcification of more than half of the mitral annular circumference.

Results

 A total of 343 patients were enrolled in the study. The mean age of the population was 80 ± 8 years, 45% were male. Mean functional area was 0.75 ± 0.18 cm2, mean transvalvular pressure gradient was 48 ± 15 mmHg and the mean left ventricular ejection fraction (LVEF) was 54 ± 14%.  MAC was detected in 231 (67%) patients. In 44 (19%) of these patients, MAC was graded as severe. Patients with severe MAC tended to have higher prevalence of moderate (27.3 vs 20.4%, p = 0.30) as well as severe (4.5 vs 1.8%, p = 0.24) mitral regurgitation at baseline. After TAVI, the prevalence of moderate mitral regurgitation at 6 months was similar between both groups (22.5 vs 20.4%, p = 0.76). Although not reaching statistical significance, patients with severe MAC had higher prevalence of severe mitral regurgitation at 6 months post-procedure (12.2 VS 5.0%, p = 0.07) as well as higher incidence of worsening of mitral regurgitation (34.2 vs 23.7%, p = 0.16). The proportion of patients that had improvement (13.2 vs 15.0%, p = 0.76) or no change (52.6 vs 61.3%, p = 0.31) in the degree of mitral regurgitation was similar in both groups. 

Conclusion

 The presence of severe MAC at baseline echocardiography in patients undergoing TAVI may be associated with worsening of mitral regurgitation after the procedure. These patients tend to have higher prevalence of severe mitral regurgitation post-TAVI. Further studies are needed in order to further elucidate this association.

Can aortic calcium score predict new conduction disturbances in pos-transcatheter aortic valve implantation?

Funding Acknowledgements

Type of funding sources: None.

Background

Transcatheter aortic valve implantation (TAVI) may be the first line treatment for severe aortic stenosis according to overall patient characteristics. Semi-quantitative Agatston score (AS), which quantifies aortic calcium by cardiac computed tomography (CCT), has knowledgeable practical and clinical implications, and is performed in TAVI diagnostic workup. Since conduction disturbances continue to be the most frequent complication, further refinements are required to predict high-risk patients.

Purpose

To access if aortic AS relates with new conduction disturbances and permanent pacemaker (PPM) implantation in patients undergoing TAVI.

Methods

We retrospectively analyzed all patients who underwent TAVI at a tertiary center from October 2014 to November 2019; patients with previous permanent pacemaker (PPM) or had no aortic AS were excluded. Clinical and electrocardiogram (ECG) data were collected at admission and after the procedure. All categorical variables are reported as numbers and percentages. Continuous variables were analyzed using the two-tailed unpaired Student’s t-test and are reported as mean values and the standard deviation. Statistical analysis was performed using the IBM SPSS.

Results

172 patients with a mean age 79 ± 9.1 years old were included (see table 1 for baseline characteristics). AS was on average 3008 ± 2262 (see table 2 for remaining diagnostic workup and procedure characteristics).

Comparing AS with new conduction disturbances, no statistically significant difference was found for new complete left branch block (LBBB) (no vs new LBBB, AS: 3179 ± 2555 vs 2637 ± 1388, p= 0,15) and with new complete atrioventricular block (AVB) (no vs new AVB, AS: 2834 ± 1520 vs 4485 ± 5285, p = 0.2). Considering PPM implantation after TAVI, there was a tendency for higher AS and PPM implantation (no vs PPM implantation, AS: 2756 ± 1451 vs 4242 ± 4310, p = 0.07).

In patients who had pre-ballooning, there was no difference relating to AS; however, in patients who had no pre-ballooning there was a trend to higher AS and PPM implantation (no vs PPM implantation, AS: 2417 ± 1301 vs 4616 ± 4969, p = 0.06). No statistically significant difference was found when comparing earlier (Portico, CoreValve Evolut R) vs newer valves (CoreValve Evolut Pro; Edward Sapiens 3; Accurate Neo).

Conclusion

Aortic calcium measured by Agatston score did not show a correlation with new LBBB or new AVB after TAVI. Nevertheless, it seems to be a trend for higher AS and PPM implantation; this was more noticeable when pre-ballooning was not performed. Further studies are needed in order to further elucidate this association. Abstract Figure. Patients baseline characteristics  Abstract Figure. TAVI diagnostic workup and procedure

Modelling and treating GRIN2A developmental and epileptic encephalopathy in mice

NMDA receptors play crucial roles in excitatory synaptic transmission. Rare variants in GRIN2A encoding the GluN2A subunit are associated with a spectrum of disorders, ranging from mild speech and language delay to intractable neurodevelopmental disorders, including but not limited to developmental and epileptic encephalopathy. A de novo missense variant, p.Ser644Gly, was identified in a child with this disorder, and Grin2a knock-in mice were generated to model and extend understanding of this intractable childhood disease. Homozygous and heterozygous mutant mice exhibited altered hippocampal morphology at 2 weeks of age, and all homozygotes exhibited lethal tonic-clonic seizures by mid-third week. Heterozygous adults displayed susceptibility to induced generalized seizures, hyperactivity, repetitive and reduced anxiety behaviours, plus several unexpected features, including significant resistance to electrically-induced limbic seizures and to pentylenetetrazole induced tonic-clonic seizures. Multielectrode recordings of neuronal networks revealed hyperexcitability and altered bursting and synchronicity. In heterologous cells, mutant receptors had enhanced NMDA receptor agonist potency and slow deactivation following rapid removal of glutamate, as occurs at synapses. NMDA receptor-mediated synaptic currents in heterozygous hippocampal slices also showed a prolonged deactivation time course. Standard anti-epileptic drug monotherapy was ineffective in the patient. Introduction of NMDA receptor antagonists was correlated with a decrease in seizure burden. Chronic treatment of homozygous mouse pups with NMDA receptor antagonists significantly delayed the onset of lethal seizures but did not prevent them. These studies illustrate the power of using multiple experimental modalities to model and test therapies for severe neurodevelopmental disorders, while revealing significant biological complexities associated with GRIN2A developmental and epileptic encephalopathy.

Arfgef1 haploinsufficiency in mice alters neuronal endosome composition and decreases membrane surface postsynaptic GABAA receptors

ARFGEF1 encodes a guanine exchange factor involved in intracellular vesicle trafficking, and is a candidate gene for childhood genetic epilepsies. To model ARFGEF1 haploinsufficiency observed in a recent Lennox Gastaut Syndrome patient, we studied a frameshift mutation (Arfgef1^fs) in mice. Arfgef1^fs/+ pups exhibit signs of developmental delay, and Arfgef1^fs/+ adults have a significantly decreased threshold to induced seizures but do not experience spontaneous seizures. Histologically, the Arfgef1^fs/+ brain exhibits a disruption in the apical lining of the dentate gyrus and altered spine morphology of deep layer neurons. In primary hippocampal neuron culture, dendritic surface and synaptic but not total GABA_A receptors (GABA_AR) are reduced in Arfgef1^fs/+ neurons with an accompanying decrease in the number of GABA_AR-containing recycling endosomes in cell body. Arfgef1^fs/+ neurons also display differences in the relative ratio of Arf6⁺:Rab11⁺:TrfR⁺ recycling endosomes. Although the GABA_AR-containing early endosomes in Arfgef1^fs/+ neurons are comparable to wildtype, Arfgef1^fs/+ neurons show an increase in the number of GABA_AR-containing lysosomes in dendrite and cell body. Together, the altered endosome composition and decreased neuronal surface GABA_AR results suggests a mechanism whereby impaired neuronal inhibition leads to seizure susceptibility.

Distinct roles for REV-ERBα and REV-ERBβ in oxidative capacity and mitochondrial biogenesis in skeletal muscle

The nuclear receptors REV-ERBα and REV-ERBβ have been demonstrated to be core members of the circadian clock and participate in the regulation of a diverse set of metabolic functions. Due to their overlapping tissue expression patterns and gene expression profiles, REV-ERBβ is thought to be redundant to REV-ERBα. Recent work has highlighted REV-ERBα's role in the regulation of skeletal muscle oxidative capacity and mitochondrial biogenesis. Considering the similarity between the REV-ERBs and the hypothesized overlap in function, we sought to determine whether REV-ERBβ-deficiency presented with a similar skeletal muscle phenotype as REV-ERBα-deficiency. Ectopic overexpression in C2C12 cells demonstrated that REV-ERBβ drives mitochondrial biogenesis and the expression of genes involved in fatty acid oxidation. Intriguingly, knock down of REV-ERBβ in C2C12 cultures also resulted in mitochondrial biogenesis and increased expression of genes involved in fatty acid β-oxidation. To determine whether these effects occurred in vivo, we examined REV-ERBβ-deficient mice and observed a similar increase in expression of genes involved in mitochondrial biogenesis and fatty acid β-oxidation. Consistent with these results, REV-ERBβ-deficient mice exhibited an altered metabolic phenotype compared to wild-type littermate controls when measured by indirect calorimetry. This likely compensated for the increased food consumption that occurred, possibly aiding in the maintenance of their weight over time. Since feeding behaviors are a direct circadian output, this study suggests that REV-ERBβ may have more subtle effects on circadian behaviors than originally identified. Furthermore, these data implicate REV-ERBβ in the control of skeletal muscle metabolism and energy expenditure and suggest that development of REV-ERBα versus REV-ERBβ selective ligands may have therapeutic utility in the treatment of metabolic syndrome.

Pharmacological Targeting the REV-ERBs in Sleep/Wake Regulation

The circadian clock maintains appropriate timing for a wide range of behaviors and physiological processes. Circadian behaviors such as sleep and wakefulness are intrinsically dependent on the precise oscillation of the endogenous molecular machinery that regulates the circadian clock. The identical core clock machinery regulates myriad endocrine and metabolic functions providing a link between sleep and metabolic health. The REV-ERBs (REV-ERBα and REV-ERBβ) are nuclear receptors that are key regulators of the molecular clock and have been successfully targeted using small molecule ligands. Recent studies in mice suggest that REV-ERB-specific synthetic agonists modulate metabolic activity as well as alter sleep architecture, inducing wakefulness during the light period. Therefore, these small molecules represent unique tools to extensively study REV-ERB regulation of sleep and wakefulness. In these studies, our aim was to further investigate the therapeutic potential of targeting the REV-ERBs for regulation of sleep by characterizing efficacy, and optimal dosing time of the REV-ERB agonist SR9009 using electroencephalographic (EEG) recordings. Applying different experimental paradigms in mice, our studies establish that SR9009 does not lose efficacy when administered more than once a day, nor does tolerance develop when administered once a day over a three-day dosing regimen. Moreover, through use of a time response paradigm, we determined that although there is an optimal time for administration of SR9009 in terms of maximal efficacy, there is a 12-hour window in which SR9009 elicited a response. Our studies indicate that the REV-ERBs are potential therapeutic targets for treating sleep problems as those encountered as a consequence of shift work or jet lag.

Correction: Pharmacological and Genetic Modulation of REV-ERB Activity and Expression Affects Orexigenic Gene Expression

[This corrects the article DOI: 10.1371/journal.pone.0151014.].

Pharmacological and Genetic Modulation of REV-ERB Activity and Expression Affects Orexigenic Gene Expression

The nuclear receptors REV-ERBα and REV-ERBβ are transcription factors that play pivotal roles in the regulation of the circadian rhythm and various metabolic processes. The circadian rhythm is an endogenous mechanism, which generates entrainable biological changes that follow a 24-hour period. It regulates a number of physiological processes, including sleep/wakeful cycles and feeding behaviors. We recently demonstrated that REV-ERB-specific small molecules affect sleep and anxiety. The orexinergic system also plays a significant role in mammalian physiology and behavior, including the regulation of sleep and food intake. Importantly, orexin genes are expressed in a circadian manner. Given these overlaps in function and circadian expression, we wanted to determine whether the REV-ERBs might regulate orexin. We found that acute in vivo modulation of REV-ERB activity, with the REV-ERB-specific synthetic ligand SR9009, affects the circadian expression of orexinergic genes in mice. Long term dosing with SR9009 also suppresses orexinergic gene expression in mice. Finally, REV-ERBβ-deficient mice present with increased orexinergic transcripts. These data suggest that the REV-ERBs may be involved in the repression of orexinergic gene expression.

Eculizumab Salvage Therapy for Antibody-Mediated Rejection in a Desensitization-Resistant Intestinal Re-Transplant Patient

The presence of elevated calculated panel reactive antibody (cPRA) and anti-HLA donor specific antibodies (DSA) are high risk factors for acute antibody-mediated rejection (AAMR) in intestinal transplantation that may lead to graft loss. Eculizumab has been used for the treatment of AAMR in kidney transplantation of sensitized patients that do not respond to other treatment. Here, we report a case where eculizumab was used to treat AAMR in a desensitization-resistant intestinal re-transplant patient. A male patient lost his intestinal graft to AAMR 8.14 years after his primary transplant. He received a second intestinal graft that had to be explanted a month later due to refractory AAMR. The patient remained highly sensitized despite multiple treatments. He received a multivisceral graft and presented with severe AAMR on day 3 posttransplantation. The AAMR was successfully treated with eculizumab. The patient presently maintains an elevated cPRA level above 90% but his DSAs have decreased from 18 000 MFI (mean fluorescent intensity) to below the positive cut-off value of 3000 MFI and remains rejection free with a 2-year follow-up since his multivisceral transplant. Eculizumab offers an alternative to treat AAMR in intestinal transplantation in desensitization-resistant patients.

Pharmacological targeting of the mammalian clock regulates sleep architecture and emotional behaviour

Synthetic drug-like molecules that directly modulate the activity of key clock proteins offer the potential to directly modulate the endogenous circadian rhythm and treat diseases associated with clock dysfunction. Here we demonstrate that synthetic ligands targeting a key component of the mammalian clock, the nuclear receptors REV-ERBα and β, regulate sleep architecture and emotional behaviour in mice. REV-ERB agonists induce wakefulness and reduce REM and slow-wave sleep. Interestingly, REV-ERB agonists also reduce anxiety-like behaviour. These data are consistent with increased anxiety-like behaviour of REV-ERBβ-null mice, in which REV-ERB agonists have no effect. These results indicate that pharmacological targeting of REV-ERB may lead to the development of novel therapeutics to treat sleep disorders and anxiety.

Quantifying Drosophila food intake: comparative analysis of current methodology

Food intake is a fundamental parameter in animal studies. Despite the prevalent use of Drosophila in laboratory research, precise measurements of food intake remain challenging in this model organism. Here, we compare several common Drosophila feeding assays: the Capillary Feeder (CAFE), food-labeling with a radioactive tracer or a colorimetric dye, and observations of proboscis extension (PE). We show that the CAFE and radioisotope-labeling provide the most consistent results, have the highest sensitivity, and can resolve differences in feeding that dye-labeling and PE fail to distinguish. We conclude that performing the radiolabeling and CAFE assays in parallel is currently the best approach for quantifying Drosophila food intake. Understanding the strengths and limitations of food intake methodology will greatly advance Drosophila studies of nutrition, behavior, and disease.

MicroRNA signature of intestinal acute cellular rejection in formalin-fixed paraffin-embedded mucosal biopsies

Despite continuous improvement of immunosuppression, small bowel transplantation (SBT) is plagued by a high incidence of acute cellular rejection (ACR) that is frequently intractable. Therefore, there is a need to uncover novel insights that will lead to strategies to achieve better control of ACR. We hypothesized that particular miRNAs provide critical regulation of the intragraft immune response. The aim of our study was to identify miRNAs involved in intestinal ACR. We examined 26 small intestinal mucosal biopsies (AR/NR group; 15/11) obtained from recipients after SBT or multivisceral transplantation. We investigated the expression of 384 mature human miRNAs and 280 mRNAs associated with immune, inflammation and apoptosis processes. We identified differentially expressed 28 miRNAs and 58 mRNAs that characterized intestinal ACR. We found a strong positive correlation between the intragraft expression levels of three miRNAs (miR-142-3p, miR-886-3p and miR-132) and 17 mRNAs including CTLA4 and GZMB. We visualized these miRNAs within cells expressing CD3 and CD14 proteins in explanted intestinal allografts with severe ACR. Our data suggested that miRNAs have a critical role in the activation of infiltrating cells during intestinal ACR. These differences in miRNA expression patterns can be used to identify novel biomarkers and therapeutic targets for immunosuppressive agents.

Long-term results of biofeedback treatment for faecal incontinence: a comparative study with untreated controls

AIM

Long-term results of biofeedback for faecal incontinence are controversial. Moreover, its value compared with standard care has been recently questioned. The study aimed to analyse the long-term efficacy of biofeedback therapy for faecal incontinence to formed stool and to compare it with no treatment.

METHOD

Seventy-nine patients with faecal incontinence to solid stool were evaluated at baseline and 1, 6, 36 and 60 months after treatment. To compare the long-term results with no treatment, 40 patients initially evaluated but not referred for therapy were used as controls.

RESULTS

More than 80% of patients recovered continence or had a reduction in the number of episodes of incontinence greater than 75% at 1, 6, 36 and 60 months, indicating that the success rate of biofeedback was maintained over time. At 60 months, 86% of patients treated with biofeedback were fully continent or had a > 75% reduction in the number of incontinent episodes compared to 26% of the untreated patients (P < 0.001).

CONCLUSION

Biofeedback therapy is effective in patients with faecal incontinence to formed stool compared with no treatment. Overall, clinical improvement is maintained in the long term.

Dynamical origin of spectrally rich vocalizations in birdsong

Birdsong is a model system for learned vocal behavior with remarkable parallels to human vocal development and sound production mechanisms. Upper vocal tract filtering plays an important role in human speech, and its importance has recently also been recognized in birdsong. However, the mechanisms of how the avian sound source might contribute to spectral richness are largely unknown. Here we show in the most widely studied songbird, the zebra finch (Taeniopygia guttata), that the broad range of upper harmonic content in different low-frequency song elements is the fingerprint of the dynamics displayed by its vocal apparatus, which can be captured by a two-dimensional dynamical model. As in human speech and singing, the varying harmonic content of birdsong is not only the result of vocal tract filtering but of a varying degree of tonality emerging from the sound source. The spectral content carries a strong signature of the intrinsic dynamics of the sound source.

Dialysis outcomes in Colombia (DOC) study: a comparison of patient survival on peritoneal dialysis vs hemodialysis in Colombia

The goal of the Dialysis Outcomes in Colombia (DOC) study was to compare the survival of patients on hemodialysis (HD) vs peritoneal dialysis (PD) in a network of renal units in Colombia. The DOC study examined a historical cohort of incident patients starting dialysis therapy between 1 January 2001 and 1 December 2003 and followed until 1 December 2005, measuring demographic, socioeconomic, and clinical variables. Only patients older than 18 years were included. As-treated and intention-to-treat statistical analyses were performed using the Kaplan-Meier method and Cox proportional hazard model. There were 1094 eligible patients in total and 923 were actually enrolled: 47.3% started HD therapy and 52.7% started PD therapy. Of the patients studied, 751 (81.3%) remained in their initial therapy until the end of the follow-up period, death, or censorship. Age, sex, weight, height, body mass index, creatinine, calcium, and Subjective Global Assessment (SGA) variables did not show statistically significant differences between the two treatment groups. Diabetes, socioeconomic level, educational level, phosphorus, Charlson Co-morbidity Index, and cardiovascular history did show a difference, and were less favorable for patients on PD. Residual renal function was greater for PD patients. Also, there were differences in the median survival time between groups: 27.2 months for PD vs 23.1 months for HD (P=0.001) by the intention-to-treat approach; and 24.5 months for PD vs 16.7 months for HD (P<0.001) by the as-treated approach. When performing univariate Cox analyses using the intention-to-treat approach, associations were with age > or =65 years (hazard ratio (HR)=2.21; confidence interval (CI) 95% (1.77-2.755); P<0.001); history of cardiovascular disease (HR=1.96; CI 95% (1.58-2.90); P<0.001); diabetes (HR=2.34; CI 95% (1.88-2.90); P<0.001); and SGA (mild or moderate-severe malnutrition) (HR=1.47; CI 95% (1.17-1.79); P=0.001); but no association was found with gender (HR=1.03, CI 95% 0.83-1.27; P=0.786). Similar results were found with the as-treated approach, with additional associations found with Charlson Index (0-2) (HR=0.29; Cl 95% (0.22-0.38); P<0.001); Charlson Index (3-4) (HR=0.61; Cl 95% (0.48-0.79); P<0.001); and SGA (mild-severe malnutrition) (HR=1.43; Cl 95% (1.15-1.77); P<0.001). Similarly, the multivariate Cox model was run with the variables that had shown association in previous analyses, and it was found that the variables explaining the survival of patients with end-stage renal disease in our study were age, SGA, Charlson Comorbidity Index 5 and above, diabetes, healthcare regimes I and II, and socioeconomic level 2. The results of Cox proportional risk model in both the as-treated and intention-to-treat analyses showed that there were no statistically significant differences in survival of PD and HD patients: intention-to-treat HD/PD (HR 1.127; CI 95%: 0.855-1.484) and as-treated HD/PD (HR 1.231; CI 95%: 0.976-1.553). In this historical cohort of incident patients, there was a trend, although not statistically significant, for a higher (12.7%) adjusted mortality risk associated with HD when compared to PD, even though the PD patients were poorer, were more likely to be diabetic, and had higher co-morbidity scores than the HD patients. The variables that most influenced survival were age, diabetes, comorbidity, healthcare regime, socioeconomic level, nutrition, and education.

Ischemic pre-conditioning in deceased donor liver transplantation: a prospective randomized clinical trial

To assess the immediate and long-term effects of ischemic preconditioning (IPC) in deceased donor. liver transplantation (LT), we designed a prospective, randomized controlled trial involving 60 donors: control group (CTL, n = 30) or study group (IPC, n = 30). IPC was induced by 10-min hiliar clamping immediately before recovery of organs. Clinical data and blood and liver samples were obtained in the donor and in the recipient for measurements. IPC significantly improved biochemical markers of liver cell function such as uric acid, hyaluronic acid and Hypoxia-Induced Factor-1 alpha (HIF-1 alpha) levels. Moreover, the degree of apoptosis was significantly lower in the IPC group. On clinical basis, IPC significantly improved the serum aspartate aminotransferase (AST) levels and reduced the need for reoperation in the postoperative period. Moreover, the incidence of primary nonfunction (PNF) was lower in the IPC group, but did not achieve statistical significance. We conclude that 10-min IPC protects against I/R injury in deceased donor LT.

Clinical trial on the cost-effectiveness of T-tube use in an established deceased donor liver transplantation program

The aim of our study was to assess the advantages and disadvantages of T-tube use in liver transplantation, with also paying attention to the economic costs derived from its use. Patients were prospectively randomized to T tube or no T tube. One hundred and seven patients, 53 with T tube and 54 without T tube, were analyzed. Minimum follow-up was three months. Nine patients (8.4%) had bile leak: six in the T-tube group (11.3%) and three in the group without T tube (5.5%), p = ns. Four patients (3.5%) had anastomotic biliary stenosis: one in the T-tube group (1.8%) and three in the group without T tube, p = ns. Twenty of the 53 patients (37.7%) with T tube had T-tube-related complication. The number of diagnostic and therapeutic resources were higher in the T-tube group compared with non-T tube (81 and 17 vs. 18 and 10, respectively, p <0.05). The costs of therapeutic procedures required for the treatment of complications were 28 232 euro in the T-tube group vs. 16 088 euro in the no T-tube group, p <0.05. In conclusion, the systematic use of the T tube in biliary reconstruction in liver transplantation cannot be justified.

Dynamical systems techniques reveal the sexual dimorphic nature of motor patterns in birdsong

In this work we analyze the pressure motor patterns used by canaries (Serinus canaria) during song, both in the cases of males and testosterone treated females. We found a qualitative difference between them which was not obvious from the acoustical features of the uttered songs. We also show the diversity of patterns, both for males and females, to be consistent with a recently proposed model for the dynamics of the oscine respiratory system. The model not only allows us to reproduce qualitative features of the different pressure patterns, but also to account for all the diversity of pressure patterns found in females.

Nm 283, an efficient prodrug of the potent anti-HCV agent 2'-C-methylcytidine

In order to improve the oral bioavailability of 2-C-methylcytidine, a potent anti-HCV agent, the corresponding 3'-O-L-valinyl ester derivative (NM 283) has been synthesized Based on its ease of synthesis and its physicochemical properties, NM 283 has emerged as a promising antiviral drug for treatment of chronic HCV infection.