Paravalvular leak closure after TAVI with plugs: A literature review with a specific focus on arterio-arterial loop.

More than mild paravalvular leak (PVL) following transcatheter aortic valve implantation (TAVI) is associated with a twofold increase in all-cause mortality, heart failure hospitalizations, and the need for reintervention. Successfully addressing PVL in TAVIs is more challenging than in surgical valves. The arterial-arterial (A-A) rail technique emerges as a valuable strategy for post-TAVI PVL closure, enhancing success rates by enabling the effective use of lower-profile vascular plug devices. When standard approach is ineffective, generating an A-A loop for post-TAVI PVL closure is probably the most recommended strategy to ensure procedural success.

CACS, CCTA and mCAD-LT score in the pre-transplant assessment of coronary artery disease and the prediction of post-transplant cardiovascular events.

BACKGROUND: The optimal cardiovascular assessment of liver transplant (LT) candidates is unclear. We aimed to evaluate the performance of CT-based coronary tests (coronary artery calcium score [CACS] and coronary CT angiography [CCTA]) and a modification of the CAD-LT score (mCAD-LT, excluding family history of CAD) to diagnose significant coronary artery disease (CAD) before LT and predict the incidence of post-LT cardiovascular events (CVE). METHODS: We retrospectively analysed a single-centre cohort of LT candidates who underwent non-invasive tests; invasive coronary angiography (ICA) was performed depending on the results of non-invasive tests. mCAD-LT was calculated in all patients. RESULTS: Six-hundred-and-thirty-four LT candidates were assessed and 351 of them underwent LT. CACS, CCTA and ICA were performed in 245, 123 and 120 LT candidates, respectively. Significant CAD was found in 30% of patients undergoing ICA. The AUROCs of mCAD-LT (.722) and CCTA (.654) were significantly higher than that of CACS (.502) to predict the presence of significant CAD. Specificity of the tests ranged between 31% for CCTA and 53% for CACS. Among patients who underwent LT, CACS ≥ 400 and mCAD-LT were independently associated with the incidence of CVE; in patients who underwent CCTA before LT, significant CAD at CCTA also predicted post-LT CVE. CONCLUSION: In this cohort, mCAD-LT score and CT-based tests detect the presence of significant CAD in LT candidates, although they tend to overestimate it. Both mCAD-LT score and CT-based tests classify LT recipients according to their risk of post-LT CVE and can be used to improve post-LT risk mitigation.

Abdominal normothermic regional perfusion in controlled donation after circulatory determination of death liver transplantation: Outcomes and risk factors for graft loss.

Postmortem normothermic regional perfusion (NRP) is a rising preservation strategy in controlled donation after circulatory determination of death (cDCD). Herein, we present results for cDCD liver transplants performed in Spain 2012-2019, with outcomes evaluated through December 31, 2020. Results were analyzed retrospectively and according to recovery technique (abdominal NRP [A-NRP] or standard rapid recovery [SRR]). During the study period, 545 cDCD liver transplants were performed with A-NRP and 258 with SRR. Median donor age was 59 years (interquartile range 49-67 years). Adjusted risk estimates were improved with A-NRP for overall biliary complications (OR 0.300, 95% CI 0.197-0.459, p < .001), ischemic type biliary lesions (OR 0.112, 95% CI 0.042-0.299, p < .001), graft loss (HR 0.371, 95% CI 0.267-0.516, p < .001), and patient death (HR 0.540, 95% CI 0.373-0.781, p = .001). Cold ischemia time (HR 1.004, 95% CI 1.001-1.007, p = .021) and re-transplantation indication (HR 9.552, 95% CI 3.519-25.930, p < .001) were significant independent predictors for graft loss among cDCD livers with A-NRP. While use of A-NRP helps overcome traditional limitations in cDCD liver transplantation, opportunity for improvement remains for cases with prolonged cold ischemia and/or technically complex recipients, indicating a potential role for complimentary ex situ perfusion preservation techniques.

Infective Endocarditis: New Challenges in a Classic Disease.

Infective endocarditis is a relatively rare, but deadly infection, with an overall mortality of around 20% in most series. Clinical manifestations have evolved in response to significant epidemiological shifts in industrialized nations, with a move toward a nosocomial or health-care-related pattern, in older patients, with more episodes associated with prostheses and/or intravascular electronic devices and a predominance of staphylococcal and enterococcal etiology.Diagnosis is often challenging and is based on the conjunction of clinical, microbiological, and imaging information, with notable progress in recent years in the accuracy of echocardiographic data, coupled with the recent emergence of other useful imaging techniques such as cardiac computed tomography (CT) and nuclear medicine tools, particularly 18F-fluorodeoxyglucose positron emission/CT.The choice of an appropriate treatment for each specific case is complex, both in terms of the selection of the appropriate agent and doses and durations of therapy as well as the possibility of using combined bactericidal antibiotic regimens in the initial phase and finalizing treatment at home in patients with good evolution with outpatient oral or parenteral antimicrobial therapies programs. A relevant proportion of patients will also require valve surgery during the active phase of treatment, the timing of which is extremely difficult to define. For all the above, the management of infective endocarditis requires a close collaboration of multidisciplinary endocarditis teams.

Improved short-term outcomes of kidney transplants in controlled donation after the circulatory determination of death with the use of normothermic regional perfusion.

Normothermic regional perfusion (NRP) allows the in situ perfusion of organs with oxygenated blood in donation after the circulatory determination of death (DCDD). We aimed at evaluating the impact of NRP on the short-term outcomes of kidney transplants in controlled DCDD (cDCDD). This is a multicenter, nationwide, retrospective study comparing cDCDD kidneys obtained with NRP versus the standard rapid recovery (RR) technique. During 2012-2018, 2302 cDCDD adult kidney transplants were performed in Spain using NRP (n = 865) or RR (n = 1437). The study groups differed in donor and recipient age, warm, and cold ischemic time and use of ex situ machine perfusion. Transplants in the NRP group were more frequently performed in high-volume centers (≥90 transplants/year). Through matching by propensity score, two cohorts with a total of 770 patients were obtained. After the matching, no statistically significant differences were observed between the groups in terms of primary nonfunction (p = .261) and mortality at 1 year (p =  .111). However, the RR of kidneys was associated with a significantly increased odds of delayed graft function (OR 1.97 [95% CI 1.43-2.72]; p < .001) and 1-year graft loss (OR 1.77 [95% CI 1.01-3.17]; p = .034). In conclusion, compared with RR, NRP appears to improve the short-term outcomes of cDCDD kidney transplants.

Development of High-Level Daptomycin Resistance in Abiotrophia and Granulicatella Species Isolates from Patients with Infective Endocarditis.

Abiotrophia and Granulicatella species are fastidious organisms, representing the causative agents of ∼1% to 3% of cases of infective endocarditis (IE). Little is known about the optimal antibiotic treatment for these species, and daptomycin has been suggested as a therapeutic option. We describe the antimicrobial profiles of Abiotrophia and Granulicatella IE isolates, investigate high-level daptomycin resistance (HLDR) development, and evaluate daptomycin activity in combination therapy. In vitro studies with 16 IE strains (6 Abiotrophia defectiva strains, 9 Granulicatella adiacens strains, and 1 G. elegans strain) were performed using microdilution to determine MICs and time-kill methodology to evaluate combination therapy. Daptomycin nonsusceptibility (DNS) (MIC ≥ 2 mg/liter) and HLDR (MIC ≥ 256 mg/liter) were based on existing Clinical and Laboratory Standards Institute (CLSI) breakpoints for viridans group streptococci. All isolates were susceptible to vancomycin: G. adiacens was more susceptible to penicillin and ampicillin than A. defectiva (22% versus 0% and 67% versus 33%) but less susceptible to ceftriaxone and daptomycin (56% versus 83% and 11% versus 50%). HLDR developed in both A. defectiva (33%) and G. adiacens (78%) after 24 h of exposure to daptomycin. Combination therapy did not prevent the development of daptomycin resistance with ampicillin (2/3 strains), gentamicin (2/3 strains), ceftriaxone (2/3 strains), or ceftaroline (2/3 strains). Once developed, HLDR was stable for a prolonged time (>3 weeks) in G. adiacens, whereas in A. defectiva, HLDR reversed to the baseline MIC at day 10. This study is the first to demonstrate rapid HLDR development in Abiotrophia and Granulicatella species in vitro. Resistance was stable, and most combination therapies did not prevent it.

Effectiveness of vancomycin plus cloxacillin compared with vancomycin, cloxacillin and daptomycin single therapies in the treatment of methicillin-resistant and methicillin-susceptible Staphylococcus aureus in a rabbit model of experimental endocarditis.

OBJECTIVES: To investigate if the addition of cloxacillin to vancomycin enhances the activity of both monotherapies for treating MSSA and MRSA experimental endocarditis (EE) in rabbits. METHODS: Vancomycin plus cloxacillin was compared with the respective monotherapies and daptomycin. In vitro time-kill studies were performed using standard (105 cfu) and high (108 cfu) inocula of five MRSA, one glycopeptide-intermediate (GISA) and five MSSA strains. One MSSA (MSSA-678) and one MRSA (MRSA-277) strain were selected to be used in the in vivo model. A human-like pharmacokinetics model was applied and the equivalents of cloxacillin 2 g/4 h IV and daptomycin 6 mg/kg/day IV were administered. To optimize vancomycin activity, dosage was adjusted to achieve an AUC/MIC ≥400. RESULTS: Daptomycin sterilized significantly more vegetations than cloxacillin (13/13, 100% versus 9/15, 60%; P = 0.02) and showed a trend of better activity than vancomycin (10/14, 71%; P = 0.09) and vancomycin plus cloxacillin (10/14, 71%; P = 0.09) against MSSA-678. Addition of cloxacillin to vancomycin (13/15, 87%) was significantly more effective than vancomycin (8/16, 50%; P = 0.05) and showed similar activity to daptomycin (13/18, 72%; P = 0.6) against MRSA-277. In all treatment arms, the bacterial isolates recovered from vegetations were re-tested and showed the same daptomycin susceptibility as the original strains. CONCLUSIONS: Vancomycin plus cloxacillin proved synergistic and bactericidal activity against MRSA. Daptomycin was the most efficacious option against MSSA and similar to vancomycin plus cloxacillin against MRSA. In settings with high MRSA prevalence, vancomycin plus cloxacillin might be a good alternative for empirical therapy of S. aureus IE.

Cloxacillin or fosfomycin plus daptomycin combinations are more active than cloxacillin monotherapy or combined with gentamicin against MSSA in a rabbit model of experimental endocarditis.

BACKGROUND: In vitro and in vivo activity of daptomycin alone or plus either cloxacillin or fosfomycin compared with cloxacillin alone and cloxacillin plus gentamicin were evaluated in a rabbit model of MSSA experimental endocarditis (EE). METHODS: Five MSSA strains were used in the in vitro time-kill studies at standard (105-106 cfu/mL) and high (108 cfu/mL) inocula. In the in vivo EE model, the following antibiotic combinations were evaluated: cloxacillin (2 g/4 h) alone or combined with gentamicin (1 mg/kg/8 h) or daptomycin (6 mg/kg once daily); and daptomycin (6 mg/kg/day) alone or combined with fosfomycin (2 g/6 h). RESULTS: At standard and high inocula, daptomycin plus fosfomycin or cloxacillin were bactericidal against 4/5 and 5/5 strains, respectively, while cloxacillin plus gentamicin was bactericidal against 3/5 strains at standard inocula but against none at high inocula. Fosfomycin, cloxacillin, gentamicin and daptomycin MIC/MBCs of the MSSA-678 strain used in the EE model were: 8/64, 0.25/0.5, 0.25/0.5 and 1/8 mg/L, respectively. Adding gentamicin to cloxacillin significantly reduced bacterial density in vegetations compared with cloxacillin monotherapy (P = 0.026). Adding fosfomycin or cloxacillin to daptomycin [10/11 (93%) and 8/11 (73%), respectively] significantly improved the efficacy of daptomycin in sterilizing vegetations [0/11 (0%), P < 0.001 for both combinations] and showed better activity than cloxacillin alone [0/10 (0%), P < 0.001 for both combinations] and cloxacillin plus gentamicin [3/10 (30%), P = 0.086 for cloxacillin plus daptomycin and P = 0.008 for fosfomycin plus daptomycin]. No recovered isolates showed increased daptomycin MIC. CONCLUSIONS: The addition of cloxacillin or fosfomycin to daptomycin is synergistic and rapidly bactericidal, showing better activity than cloxacillin plus gentamicin for treating MSSA EE, supporting their clinical use.

Clinical impact of rapid susceptibility testing on Mueller-Hinton Rapid-SIR directly from urine specimens.

Urinary tract infection diagnosis and management generally involves a 48-h microbiological delay to obtain the antibiotic susceptibility test (AST) results. In the context of multidrug resistance, reducing the time to obtain AST results is an essential factor, allowing for more timely appropriate treatment. We conducted a single-centre prospective study on urinary samples meeting two criteria: significant leukocyturia > 50/mm3 and exclusive presence of Gram-negative bacilli on direct examination. AST were performed by direct inoculation on Mueller-Hinton Rapid-SIR (MHR-SIR) agar. We evaluated the time to antibiotic adaptation by the antimicrobial stewardship team according to rapid AST results. Patients were subsequently excluded from the study if asymptomatic bacteria were confirmed, or in the absence of clinical data. Seventy patients were included. Mean age of patients was 68.8 years (± 21.3). Empirical antibiotic treatment were mainly based on third generation cephalosporins (n = 33), fluoroquinolones (n = 15), beta-lactamin/beta-lactamase inhibitors (n = 7), fosfomycin and nitrofurantoin (n = 5, each). The average time to obtain results was 7.2 h (± 1.6 h). Adaptation of therapy following MHR-SIR was performed for 29 patients (41%) with early switch to oral antibiotics, de-escalation or escalation in respectively 72.3%, 30%, and 11% of cases. Time saving of MHR-SIR compared with the standard technique was 42.6 (± 16.7) h. This study showed that rapid antibiotic susceptibility test results, using MHR-SIR method directly from urine, can be obtained 40 h earlier than conventional AST. The study also demonstrated significant clinical impact on the selection and reduction of the antibiotic therapy spectrum.

Impact of a multiplex PCR assay (FilmArray®) on the management of patients with suspected central nervous system infections.

Microbiological diagnosis of central nervous system (CNS) infections is challenging due to limited access to CNS samples, overlap between meningitis and encephalitis, and the multiplicity of pathogens potentially involved. We aimed to estimate the impact of a commercial multiplex PCR assay (FilmArray® meningitis/encephalitis) on the management of patients with suspicion of meningitis or encephalitis, in terms of time to diagnosis, antimicrobial agents use, duration of hospitalization, and costs. This prospective observational study was conducted at Saint Joseph Hospital (Paris, France) from December 2016 to December 2017. All CSF samples sent to the microbiology laboratory for suspicion of meningitis and/or encephalitis, with CSF cells count > 5 cells/µL, were tested by meningitis/encephalitis multiplex PCR assay. One hundred thirty patients were included. The multiplex PCR assay was positive in 33 patients (25%). Main pathogens found were Enterovirus (n = 12), Varicella-Zoster virus (n = 7), Herpes simplex virus-2 (n = 6), and Listeria monocytogenes (n = 3) as main pathogens. The multiplex PCR assay reduced time to microbiological diagnosis by 3.3 ± 1.6 days and allowed an earlier discontinuation of empirical anti-infective drugs in 42 patients (32%) and an earlier hospital discharge in 23 patients (18%), with an estimated saving of 82 hospital days overall, and a management cost reduction of 26,242 € (201 €/patient). The systematic use of the FilmArray® meningitis/encephalitis multiplex PCR assay may allow earlier diagnosis, earlier discontinuation of empirical treatment, reduced duration of stay, and costs reduction.

A high-grade glioma with SOS1 amplification.

The molecular alterations underlying progression of low-grade glial/glioneuronal tumors remain to be elucidated. We present a case of a 56-year-old male with an enhancing left temporal lobe tumor. Histology revealed a high-grade glioma adjacent to a low-grade glioneuronal component with abundant Rosenthal fibers, focal eosinophilic granular bodies, and CD34-positive neurons. The tumor was negative for IDH1 (R132H), BRAF-V600E, and the KIAA1549-BRAF fusion. Comparative genomic hybridization detected a large amplification (> 15 copies) of the Son of Sevenless 1 (SOS1) gene, a component of the MAPK pathway. Although activating mutations in the MAPK pathway occur frequently in gliomas and glioneuronal tumors, SOS1 gene amplification has not been reported previously. This case indicates another potential mechanism for MAPK activation in glial tumors.

Clinical impact of rapid susceptibility testing on MHR-SIR directly from blood cultures.

BACKGROUND: In a previous study, we demonstrated that rapid antibiotic susceptibility tests (ASTs) can be performed directly on blood culture samples tested on Mueller-Hinton Rapid agar (MHR-SIR) with a time delay of 6-8 h. OBJECTIVES: Using this rapid disc diffusion method, we analysed the clinical impact associated with rapid reporting of results in our hospital setting. METHODS: All patients with bloodstream infections (BSIs) related to Enterobacteriaceae or Staphylococcus aureus were prospectively included in the study. The rapid ASTs were performed by incubation of positive blood cultures on MHR-SIR for 6-8 h by direct inoculation according to BSAC recommendations. RESULTS: One hundred and sixty-seven patients with BSIs were included as MHR-guided adaptation therapy cases. Eighty percent had Enterobacteriaceae-related BSIs, of which 12 (9%) were ESBL producers and 20% were S. aureus-related BSIs. A urinary or intra-abdominal infection was observed in 44.3% and 19.8%, respectively, of Enterobacteriaceae-related infections. The most frequent sources of infections for S. aureus BSIs were cutaneous and endovascular, in 43% and 23% of cases, respectively. Forty-four percent of the patients benefited from therapeutic modification according to the results of the MHR-SIR AST. Thus, empirical antibiotic therapy was modified by using antibiotic therapy that had too wide a spectrum or was unsuitable in 26% and 18% of cases, respectively. Compared with the 24 h required for the reference method, the median length of time to provision of susceptibility test results by MHR-SIR was 7 h. CONCLUSIONS: This study showed a significant time saving (17 h) on the appropriateness of antibiotic prescription and demonstrated a significant impact regarding the choice and reduction of the spectrum of antibiotic therapy.

Performance of rapid antimicrobial susceptibility testing by disk diffusion on MHR-SIR agar directly on urine specimens.

The standard method for the diagnosis of urinary tract infections is urine culture that requires 18-48 h for the identification of the bacteria and an additional 24 h until the results of antimicrobial susceptibility testing (AST) are available. We evaluated here a rapid AST method by disc diffusion performed directly on urine samples with a delay of 8 h. A total of 245 urine samples with monobacterial Gram negative observed on microscopy were tested in parallel by two AST methods. Rapid AST method was performed directly on urine samples using Rapid Mueller-Hinton (MHR-SIR) with 8-h incubation before reading and standard method was performed as usual. We compared the categorical agreement and the correlation between the diameters obtained by standard method and by MHR-SIR directly on urine samples. Over the 5285 tested combinations, we observed 5172 (97.9%) categorical agreement, 82 (1.5%) minor errors, 17 (0.3%) major errors, and 14 (0.3%) very major errors. Our results showed an excellent categorical agreement and correlations between diameters for MHR-SIR and standard methods. MHR-SIR performed directly on urine samples with monomicrobial Enterobacteriacae can predict the result of overall AST profile in 8 h with reliable results. The main advantage of MHR-SIR is that it offers the possibility of obtaining results 40 h earlier than conventional AST. The cost is estimated for less than 6 USD for 16 antibiotics, chosen by the microbiologist.

Mechanical Thrombectomy for Acute Ischemic Stroke Secondary to Infective Endocarditis.

Intravenous thrombolysis is contraindicated in acute ischemic stroke secondary to infective endocarditis. We report our initial experience in 6 cases of proximal vessel occlusion treated with mechanical thrombectomy, which was safe (no bleeding) and effective (significant early neurological improvement) and might be useful in this clinical setting.

Epidemiology, Clinical Features, and Outcome of Infective Endocarditis due to Abiotrophia Species and Granulicatella Species: Report of 76 Cases, 2000-2015.

Background: Infective endocarditis (IE) caused by Abiotrophia (ABI) and Granulicatella (GRA) species is poorly studied. This work aims to describe and compare the main features of ABI and GRA IE. Methods: We performed a retrospective study of 12 IE institutional cases of GRA or ABI and of 64 cases published in the literature (overall, 38 ABI and 38 GRA IE cases). Results: ABI/GRA IE represented 1.51% of IE cases in our institution between 2000 and 2015, compared to 0.88% of HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella)-related IE and 16.62% of Viridans group streptococci (VGS) IE. Institutional ABI/GRA IE case characteristics were comparable to that of VGS, but periannular complications were more frequent (P = .008). Congenital heart disease was reported in 4 (10.5%) ABI and in 11 (28.9%) GRA cases (P = .04). Mitral valve was more frequently involved in ABI than in GRA (P < .001). Patient sex, prosthetic IE, aortic involvement, penicillin susceptibility, and surgical treatment were comparable between the genera. New-onset heart failure was the most frequent complication without genera differences (P = .21). Five (13.2%) ABI patients and 2 (5.3%) GRA patients died (P = .23). Factors associated with higher mortality were age (P = .02) and new-onset heart failure (P = .02). The genus (GRA vs ABI) was not associated with higher mortality (P = .23). Conclusions: GRA/ABI IE was more prevalent than HACEK IE and approximately one-tenth as prevalent as VGS; periannular complications were more frequent. GRA and ABI genera IE presented similar clinical features and outcomes. Overall mortality was low, and related to age and development of heart failure.

The Combination of Daptomycin and Fosfomycin Has Synergistic, Potent, and Rapid Bactericidal Activity against Methicillin-Resistant Staphylococcus aureus in a Rabbit Model of Experimental Endocarditis.

We investigated whether the addition of fosfomycin or cloxacillin to daptomycin provides better outcomes in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) experimental aortic endocarditis in rabbits. Five MRSA strains were used to perform in vitro time-kill studies using standard (106) and high (108) inocula. Combined therapy was compared to daptomycin monotherapy treatment in the MRSA experimental endocarditis model. A human-like pharmacokinetics model was applied, and the equivalents of cloxacillin at 2 g/4 h, fosfomycin at 2 g/6 h, and daptomycin at 6 to 10 mg/kg/day were administered intravenously. A combination of daptomycin and either fosfomycin or cloxacillin was synergistic in the five strains tested at both inocula. A bactericidal effect was detected in four of five strains tested with both combinations. The MRSA-277 strain (vancomycin MIC, 2 µg/ml) was used for the experimental endocarditis model. Daptomycin plus fosfomycin significantly improved the efficacy of daptomycin monotherapy at 6 mg/kg/day in terms of both the proportion of sterile vegetations (100% versus 72%, P = 0.046) and the decrease in the density of bacteria within the vegetations (P = 0.025). Daptomycin plus fosfomycin was as effective as daptomycin monotherapy at 10 mg/kg/day (100% versus 93%, P = 1.00) and had activity similar to that of daptomycin plus cloxacillin when daptomycin was administered at 6 mg/kg/day (100% versus 88%, P = 0.48). Daptomycin nonsusceptibility was not detected in any of the isolates recovered from vegetations. In conclusion, for the treatment of MRSA experimental endocarditis, the combination of daptomycin plus fosfomycin showed synergistic and bactericidal activity.

AUC/MIC Pharmacodynamic Target Is Not a Good Predictor of Vancomycin Efficacy in Methicillin-Resistant Staphylococcus aureus Experimental Endocarditis.

The aim of this in vivo study was to compare the efficacy of vancomycin at standard doses (VAN-SD) to that of VAN at adjusted doses (VAN-AD) in achieving a VAN area under the curve/MIC ratio (AUC/MIC) of ≥400 against three methicillin-resistant Staphylococcus aureus (MRSA) strains with different microdilution VAN MICs in an experimental endocarditis model. The valve vegetation bacterial counts after 48 h of VAN therapy were compared, and no differences were observed between the two treatment groups for any of the three strains tested. Overall, for VAN-SD and VAN-AD, the rates of sterile vegetations were 15/45 (33.3%) and 21/49 (42.8%) (P = 0.343), while the medians (interquartile ranges [IQRs]) for log10 CFU/g of vegetation were 2 (0 to 6.9) and 2 (0 to 4.5) (P = 0.384), respectively. In conclusion, this VAN AUC/MIC pharmacodynamic target was not a good predictor of vancomycin efficacy in MRSA experimental endocarditis.

Omental implantation of BOECs in hemophilia dogs results in circulating FVIII antigen and a complex immune response.

Ex vivo gene therapy strategies avoid systemic delivery of viruses thereby mitigating the risk of vector-associated immunogenicity. Previously, we delivered autologous factor VIII (FVIII)-expressing blood outgrowth endothelial cells (BOECs) to hemophilia A mice and showed that these cells remained sequestered within the implanted matrix and provided therapeutic levels of FVIII. Prior to translating this strategy into the canine (c) model of hemophilia A, we increased cFVIII transgene expression by at least 100-fold with the use of the elongation factor 1 alpha (EF1α) promoter and a strong endothelial enhancer element. BOECs isolated from hemophilia A dogs transduced with this lentiviral vector express levels of cFVIII ranging between 1.0 and 1.5 U/mL per 10(6) cells over 24 hours. Autologous BOECs have been implanted into the omentum of 2 normal and 3 hemophilia A dogs. These implanted cells formed new vessels in the omentum. All 3 hemophilia A dogs treated with FVIII-expressing autologous BOECs developed anti-FVIII immunoglobulin G2 antibodies, but in only 2 of the dogs were these antibodies inhibitory. FVIII antigen levels >40% in the absence of FVIII coagulant function were detected in the circulation for up to a year after a single gene therapy treatment, indicating prolonged cellular viability and synthesis of FVIII.

Analysis of the role of von Willebrand factor, platelet glycoprotein VI-, and α2ß1-mediated collagen binding in thrombus formation.

Rare missense mutations in the von Willebrand factor (VWF) A3 domain that disrupt collagen binding have been found in patients with a mild bleeding phenotype. However, the analysis of these aberrant VWF-collagen interactions has been limited. Here, we have developed mouse models of collagen-binding mutants and analyzed the function of the A3 domain using comprehensive in vitro and in vivo approaches. Five loss-of-function (p.S1731T, p.W1745C, p.S1783A, p.H1786D, A3 deletion) and 1 gain-of-function (p.L1757A) variants were generated in the mouse VWF complementary DNA. The results of these various assays were consistent, although the magnitude of the effects were different: the gain-of-function (p.L1757A) variant showed consistent enhanced collagen binding whereas the loss-of-function mutants showed variable degrees of functional deficit. We further analyzed the impact of direct platelet-collagen binding by blocking glycoprotein VI (GPVI) and integrin α2ß1 in our ferric chloride murine thrombosis model. The inhibition of GPVI demonstrated a comparable functional defect in thrombosis formation to the VWF(-/-) mice whereas α2ß1 inhibition demonstrated a milder bleeding phenotype. Furthermore, a delayed and markedly reduced thrombogenic response was still evident in VWF(-/-), GPVI, and α2ß1 blocked animals, suggesting that alternative primary hemostatic mechanisms can partially rescue the bleeding phenotype associated with these defects.

Valvular Heart Disease Epidemics.

BACKGROUND AIM OF THE STUDY: The real burden of valvular heart disease (VHD) is scarcely known, as several factors may potentially lead to its increased prevalence. The study aim was to assess the prevalence of VHD and its treatment in the authors' environment to plan the healthcare requisites for optimal management of the condition. METHODS: A retrospective analysis was conducted of data acquired from patients who had been assessed at different consultation levels for cardiovascular disorders during a six-month period between January and June 2014 in public health referral area of 500,00 inhabitants. Patients included were those admitted to hospital cardiology, cardiac surgery and geriatric care units (n = 1,083), as well as ambulatory patients attending cardiology-specific outpatient clinics at the authors' hospital or at two ascribed primary care centers (n = 852). Data were registered regarding the epidemiology, etiology, echocardiography and treatment of patients in whom VHD was detected. RESULTS: Among a total of 1,935 adult patients, moderate or severe valve disease was identified in 453 cases (23.4%) who were evaluated for cardiovascular disease. The prevalence of VHD increased with age. Multivalvular moderate-severe dysfunction was present in two valves in 33% and in three valves in 5.7% of patients. Significant mitral valve disease was present in 39% and aortic valve disease in 48% of patients. The etiology of the valvular lesions was degenerative in 60%, functional in 15.5%, rheumatic in almost 10%, congenital in 6%, due to endocarditis in only 3%. Patients with VHD represented up to 24.2% of the in-hospital admissions. An interventional treatment was required in 55% of the patients (mostly surgical valve procedures). CONCLUSION: The present study results showed that VHD is a frequent occurrence and is increasingly prevalent with age, constituting up to one-fourth of all in-hospital admissions for cardiovascular disease. VHD is a growing public health problem that should be addressed with appropriate resources to improve research into its nature, diagnosis and treatment.