The analysis of left ventricular ejection fraction after minimally invasive surgery for primary mitral valve regurgitation.

BACKGROUND: Although minimally invasive mitral valve surgery (MIMVS) has become the first choice for primary mitral regurgitation (MR) in recent years, clinical evidence in this field is yet limited. The main focus of this study was the analysis of preoperative (Pre), postoperative (Post), and 1-year follow-up (Fu) data in our series of MIMVS to identify factors that have an impact on the left ventricular ejection fraction (LVEF) evolution after MIMVS. METHODS: We reviewed the perioperative and 1-year follow-up data from 436 patients with primary MR (338 isolated MIMVS und 98 MIMVS combined with tricuspid valve repair) to analyze patients' baseline characteristics, the change of LV size, the postoperative evolution of LVEF and its factors, and the clinical outcomes. RESULTS: The overall mean value of ejection fraction (EF) slightly decreased at 1-year follow-up (mean change of LVEF: -2.63 ± 9.00%). A significant correlation was observed for preoperative EF (PreEF) und EF evolution, the higher PreEF the more pronounced decreased EF evolution (in all 436 patients; r = -.54, p < .001, in isolated MIMVS; r = -.54, p < .001, in combined MIMVS; r = -.53, p < .001). Statistically significant differences for negative EF evolution were evident in patients with mild or greater tricuspid valve regurgitation (TR) (in all patients; p < .05, odds ratio [OR] = 1.64, in isolated MIMVS; p < .01, OR = 1.93, respectively). Overall clinical outcome in New York Heart Association classification at 1 year was remarkably improved. CONCLUSIONS: Our results suggest an excellent clinical outcome at 1 year, although mean LVEF slightly declined over time. TR could be a predictor of worsened follow-up LVEF in patients undergoing MIMVS.

The Impact of Intraoperative Patient Blood Management on Quality Development in Cardiac Surgery.

OBJECTIVES: Patient blood management (PBM) is increasingly introduced into clinical practice. Minimizing effects on transfusion have been proven, but relevance for clinical outcome has been sparsely examined. In regard to this, the authors analyzed the impact of introducing intraoperative PBM to cardiac surgery. DESIGN: Retrospective case-control study. SETTING: Single center. PARTICIPANTS: A total of 3,170 patients who underwent either coronary artery bypass grafting, isolated aortic valve replacement, or a combined procedure at the authors' institution between January 1, 2007, and December 31, 2015. INTERVENTION: In 2013, an intraoperative PBM service was established offering therapy recommendations on the basis of real-time laboratory monitoring. Comparisons to conventional coagulation management were adjusted for optimization of general, surgical, and perioperative care standards by interrupted time-series analysis and risk-dependent confounding by propensity- score matching. MEASUREMENTS AND MAIN RESULTS: Primary study endpoints were in-hospital mortality and morbidity. Morbidity was defined as clinically relevant prolongation of hospital stay, which was related to accumulation of postoperative complications. Transfusion requirements, bleeding, and thromboembolic complications were not treated as primary endpoints, but were also explored. The recommendations on the basis of real-time laboratory monitoring were adopted by the operative team in 72% of patients. Intraoperative PBM was associated independently with a reduction of morbidity (8.3% v 6.3%, p = 0.034), whereas in-hospitalmortality (3.0% v 2.6%, p = 0.521) remained unaffected. The need for red blood cell transfusion decreased (71.1% v 65.0%, p < 0.001), as did bleeding complications requiring surgical re-exploration (3.5% v 1.8%, p = 0.004). At the same time, stroke increased by statistical trend (1.0% v 1.9%, p = 0.038; after correction for imbalanced type of surgical procedure p = 0.085). CONCLUSIONS: Real-time laboratory recommendations achieved a high acceptance rate early after initiation. Improvement of clinical outcome by intraoperative PBM adds to the optimized surgical care. However, the corridor between hemostatic optimization and thromboembolic risk may be narrow.

Cornea donation in Germany: Obtaining consent.

Tissue donation is important to reverse cornea-related blindness. Unfortunately, the willingness to make a decision concerning organ and tissue donation while still alive remains low despite all efforts. By analyzing anonymized archived data from 25 654 next-of-kin interviews from our database over a period of 5 years (2013-2018), it was found that only 20.8% of all potential cornea donors have declared their own wishes. While still alive, refusal was communicated more often than consent by potential donors. Overall consent rates were 39.2%, with parents and siblings consenting more often than other relatives and females refusing more often than male family members. Personal interviews and interviews via telephone handled by staff known to the family resulted in better consent rates (up to 75.6%) with male interviewers receiving higher consent rates in general. The gender of the approached relatives in relation to a male/female interviewer was of low importance. The results also show that it is important to allow discussion about that topic between family members-the more relatives that were involved the higher the probability of consent.

Fibrinolysis and the Influence of Tranexamic Acid Dosing in Cardiac Surgery.

OBJECTIVE: The present study aimed to determine whether underlying disease, performed surgery, and dose of tranexamic acid influence fibrinolysis measured with D-dimer levels. DESIGN: Retrospective analysis. SETTING: Single institution (Department of Cardiac Surgery and Section of Clinical Hemostaseology at the Düsseldorf University Hospital). PARTICIPANTS: The study comprised 3,152 adult patients undergoing elective cardiac surgery between February 2013 and October 2016. INTERVENTIONS: Two doses of tranexamic acid during surgery were administered. MEASUREMENTS AND MAIN RESULTS: D-dimer levels were analyzed at the start of surgery and before protamine administration. D-dimer levels at the start of surgery were compared according to disease. Intraoperative D-dimer development was analyzed according to the type of surgery and within 2 cohorts with different tranexamic acid doses. Interindividual variability was pronounced for D-dimer levels at the start of surgery, with significant differences among patients with coronary artery disease, valve disease, and aortic disease and patients undergoing heart transplantation compared with patients receiving a left ventricular assist device (p < 0.01). Aortic dissection, endocarditis, and extracorporeal life support were associated with higher D-dimer levels (p ≤ 0.01). With tranexamic acid at a fixed dose, intraoperative D-dimer levels decreased in on-pump and off-pump coronary bypass surgery, valve surgery, and left ventricular assist device surgery (p ≤ 0.02), but levels increased in aortic surgery and heart transplantations (p < 0.01). A decrease or increase in D-dimer levels during surgery was influenced significantly by a higher or lower tranexamic acid dose (p ≤ 0.01). CONCLUSIONS: D-dimer testing allows for the assessment of individual fibrinolytic activity in cardiac surgery, which is influenced by disease type, surgery type, and dose of tranexamic acid. The assessment of the fibrinolytic status may have the potential to facilitate dose-adjusted antifibrinolytic therapy in the future.

The Course of Circulating Small Extracellular Vesicles in Patients Undergoing Surgical Aortic Valve Replacement.

In the last years, increasing efforts have been devoted to investigating the role of small extracellular vesicles (sEVs) in cardiovascular diseases. These nano-sized particles (30-150 nm), secreted by different cell types, contain signalling molecules that enable participation in intercellular communication processes. In this study, we examined the course of circulating sEVs in patients undergoing surgical aortic valve replacement (SAVR) and correlated them with echocardiographic and standard blood parameters. Peripheral blood samples were collected from 135 patients undergoing SAVR preoperatively and at three follow-up points. Circulating sEVs were precipitated using Exoquick™ exosome isolation reagent and analyzed by nanoparticle tracking analysis (NTA). Our findings indicate that no more than 7 days after SAVR, there was a marked increase of circulating sEVs before returning to initial values after 3 months. Further, shear stress is not a trigger for the formation and release of circulating sEVs. Moreover, we pointed out a correlation between circulating sEVs and erythrocytes as well as LDH and creatinine levels in peripheral blood. Finally, all patients with a moderate prosthesis-patient mismatch as well as with an impaired left ventricular mass regression had lower levels of circulating sEVs 3 months after SAVR compared to their respective status before surgery. We conclude that in patients with aortic valve stenosis (AVS), sEVs may play an important part in mediating cell-cell communication and SAVR may have a crucial and lasting impact on their circulating levels. Besides, lower levels of sEVs portend to be associated with inferior recovery after major surgical interventions. The additional use of circulating sEVs beyond echocardiographic and laboratory parameters could have a prognostic value to estimate adverse outcomes in patients undergoing SAVR.

Previous Sternotomy as a Risk Factor in Minimally Invasive Mitral Valve Surgery.

BACKGROUND: Cardiac redo surgery, especially after a full sternotomy, is considered a high-risk procedure. Minimally invasive mitral valve surgery (MIMVS) is a potential therapeutic approach. However, current developments in interventional cardiology necessitate additional discussion regarding the therapy of choice in high-risk patients. In this context, it is necessary to clarify the perioperative and postoperative risks induced by the factor previous sternotomy in the setting of MIMVS. Thus, we present a comparative study analyzing the outcome of MIMVS after previous sternotomy vs. primary operation. METHODS: We identified 19 patients who received isolated or combined mitral valve (MV) surgery via the MIMVS approach after previous full sternotomy (PS group) and compared the results to those of a group of 357 patients who received primary MIMVS (non-PS group). After a propensity score analysis, groups of n = 15 and n = 131, respectively, were subjected to a comparative evaluation. A 1-year follow-up analysis of functional cardiac parameters and clinical symptoms was performed, accompanied by a Kaplan-Meier analysis. RESULTS: Except for the rate of realized MV reconstructions (PS group: 53.8% vs. non-PS group: 85.5%; p = 0.011), no significant differences were to be noted within the intraoperative and early postoperative course. However, patients in the PS group experienced an increased intensive care unit stay length (PS group: 2 days, 95% CI, 1-8 vs. non-PS group: 1 day, 95% CI, 1-2; p = 0.072). The follow-up examinations revealed excellent functional and clinical outcomes for both groups. The Kaplan-Meier analysis displayed no significant difference regarding the postoperative mortality (p = 0.929) related to the patients at risk. CONCLUSION: A previous sternotomy remains a risk factor for MIMVS and demands special attention in the early postoperative period. Nevertheless, the early- and late-term results concerning the functional and clinical outcomes suggest that the MIMVS procedure is satisfactory, even after a full sternotomy.

T lymphocytes export proteasomes by way of microparticles: a possible mechanism for generation of extracellular proteasomes.

The 20S proteasome is almost exclusively localized within cells. High levels of extracellular proteasomes are also found circulating in the blood plasma of patients suffering from a variety of inflammatory, autoimmune and neoplastic diseases. However, the origin of these proteasomes remained enigmatic. Since the proteome of microparticles, small membrane enclosed vesicles released from cells, was shown to contain proteasomal subunits, we studied whether intact proteasomes are actively released into the extracellular space. Using human primary T lymphocytes stimulated with CaCl2 and the calcium ionophore A23187 to induce membrane blebbing we demonstrate that microparticles contain proteolytically active 20S proteasomes as well as the proteasome activator PA28 and subunits of the 19S proteasome regulator. Furthermore, our experiments reveal that incubation of in vitro generated T lymphocyte-microparticles with sphingomyelinase results in the hydrolysis of the microparticle membranes and subsequent release of proteasomes from the vesicles. Thus, we here show for the first time that functional proteasomes can be exported from activated immune cells by way of microparticles, the dissolution of which may finally lead to the generation of extracellular proteasomes.

Circulating extracellular proteasome in the cerebrospinal fluid: a study on concentration and proteolytic activity.

Alterations of the intracellular ubiquitin-proteasome pathway are found in neurodegenerative and inflammatory disorders of the central nervous system, as well as in its malignancies. Inhibitory substrates of the proteasomes represent promising approaches to control autoimmune inflammations and induction of apoptosis in cancer cells. Extracellular circulating proteasomes are positively correlated to outcome prognosis in hematogenic neoplasias and the outcome in critically ill patients. Previously, we reported raised levels of proteolytic active 20S proteasomes in the extracellular alveolar space in patients with acute respiratory distress syndrome (ARDS). For the cerebrospinal fluid, we assumed that extracellular circulating proteasomes with enzymatic activity can be found, too. Cerebrospinal fluid (CSF) samples of twenty-six patients (14 females, 12 males), who underwent diagnostic spinal myelography, were analyzed for leukocyte cell count, total protein content, lactate and interleukine-6 (Il-6) concentrations. CSF samples were analyzed for concentration and enzymatic activity of extracellular 20S proteasomes (fluorescenic substrate cleavage; femtokatal). Blood samples were analyzed with respect to concentration of extracellular circulating proteasomes. Choroidal plexus was harvested at autopsies and examined with immunoelectron microscopy (EM) for identification of possible transportation mechanisms. Statistical analysis was performed using SPSS (18.0.3). In all patients, extracellular proteasome was found in the CSF. The mean concentration was 24.6 ng/ml. Enzymatic activity of the 20S subunits of proteasomes was positively identified by the fluorescenic subtrate cleavage at a mean of 8.5 fkat/ml. Concentrations of extracellular proteasomes in the CSF, total protein content and Il-6 were uncorrelated. Immunoelectron microscopy revealed merging vesicles of proteasomes with the outer cell membrane suggestive of an exozytic transport mechanism. For the first time, extracellular circulating 20S proteasome in the CSF of healthy individuals is identified and its enzymatic activity detected. A possible exozytic vesicle-bond transportation mechanism is suggested by immunoelectron microscopy. The present study raises more questions on the function of extracellular proteasome in the CSF and encourages further studies on the role of extracellular protesomes in pathological conditions of the central nervous system (tumor lesions and inflammatory processes).

Circulating 20S proteasome in patients with non-metastasized breast cancer.

BACKGROUND: Recent data suggest a role of the ubiquitin-proteasome system in various malignancies. In patients with neoplasms, increased extracellular concentrations of circulating 20S proteasome (c-proteasome) have been detected in blood plasma. We tested the hypothesis that the plasma c-proteasome concentration is a biomarker associated with tumor stage and nodal status in patients with the primary diagnosis of non-metastatic breast cancer. PATIENTS AND METHODS: Venous plasma concentration of 20S proteasome was measured by ELISA technique in 224 non-metastatic breast cancer patients and in 50 healthy volunteers. To assess the relation of proteasome expression to c-proteasome concentration, tumor specimens from 32 patients were immunohistochemically stained for 20S proteasome using an antibody directed against the core subunits of the catalytic domain of the 20S proteasome. RESULTS: The median c-proteasome concentration was higher (p<0.0001) in breast cancer patients (397.5 ng/ml, range: 200-50,000 ng/ml) than in healthy controls (305 ng/ml, range: 140-425 ng/ml). There was no significant correlation between c-proteasome concentration and strength of proteasomal staining in tumor specimens. Neither tumor size, nor nodal status, nor any other prognostically important clinical parameter, including the presence of disseminated tumor cells in the bone marrow, correlated with high c-proteasome concentrations. CONCLUSION: Circulating proteasome concentrations appear to be higher in patients presenting with primary breast cancer than in healthy controls. Thus, the ubiquitin-proteasome system might represent a potential target in breast cancer treatment.

The prognostic impact of circulating proteasome concentrations in patients with epithelial ovarian cancer.

BACKGROUND: Intracellularly, the ubiquitin-proteasome system participates in crucial functions such as cell cycling, differentiation, proliferation, gene transcription, and apoptosis. However, in malignancies including ovarian cancer increased extracellular concentrations of circulating 20S proteasomes (c-proteasomes) have been detected in blood. We tested the hypothesis that the c-proteasome plasma concentration is a biomarker associated with the clinical course of ovarian cancer patients. METHODS: 20S-proteasome venous plasma concentration was measured by ELISA in patients presenting with ovarian cancer before (n=120) and after (n=68) primary treatment, and in healthy volunteers (n=55). The median follow-up time was 19 months. To assess the relation of proteasome expression with c-proteasome concentration, tumor specimens from 27 patients were immunohistochemically stained for 20S proteasome using an antibody directed against the core subunits of the catalytic domain of the 20S proteasome. RESULTS: Median c-proteasome concentration was higher (p<0.0001) in untreated ovarian cancer patients (457.5 ng/ml, range: 200-12540 ng/ml) than in healthy controls 290 ng/ml, range: 140-425 ng/ml). Following completion of primary treatment, the median c-proteasome concentration increased (p=0.003) relative to baseline (595 ng/ml, range: 200-20000 ng/ml) and concentrations positively correlated (p=0.031) with residual disease left at primary surgery. Patients with post-treatment c-proteasome concentrations exceeding the cohort's median showed a diminished survival (p=0.045). We found no correlation between c-proteasome concentration and strength of proteasomal staining in tumor specimens. CONCLUSIONS: Circulating proteasome concentrations correlate with residual tumor mass and might be a prognostic variable in ovarian cancer following primary therapy.

Extracellular alveolar proteasome: possible role in lung injury and repair.

The ubiquitin-proteasome system is the major intracellular pathway for protein degradation in eukaryotes, and it also generates oligopeptides for antigen presentation. However, the 20S proteasome is also associated with the cell's outer membrane, and observations indicate its physiologic presence and biological activity in the extracellular alveolar space (i.e., in the epithelial lining fluid). Furthermore, its concentration is increased in the adult respiratory distress syndrome, acute lung injury, and other inflammatory lung disease. While its cellular origin, potential extracellular biological role, and mechanisms for extracellular transport are hitherto unclear, extracellular alveolar proteasomes could have a role in protein clearance, digestion of alveolar debris, modification or activation of secreted precursor proteins, and/or antigen processing, both in health and lung disease. This article summarizes available information on the extracellular alveolar proteasome and its possible role in alveolar maintainance, lung injury, and repair.

Ventricular unloading is associated with increased 20s proteasome protein expression in the myocardium.

BACKGROUND: The ubiquitin-proteasome system (UPS) breaks down misfolded and normal proteins, including cell cycle regulatory proteins involved in cardiac hypertrophy. Because congestive heart failure (CHF) increases cardiomyocyte cellular mass, indicative of increased protein synthesis and/or impaired breakdown, and ventricular unloading decreases cardiac hypertrophy and changes regulation of multiple molecular systems ("reverse cardiac remodeling"), we tested the hypothesis that ventricular unloading alters myocardial UPS. METHODS: In 23 paired myocardial specimens (before and after unloading) ubiquitin, 20S proteasome, and cyclin D1 were investigated immunohistochemically and morphometrically quantified in relation to cardiomyocyte hypertrophy, DNA content, nuclear profile area and perimeter, and cyclin D1 protein expression. Moreover, 20S proteasome plasma concentrations were measured by enzyme-linked immunoassay (ELISA). RESULTS: In CHF, sarcoplasmic 20S proteasome protein expression was significantly decreased compared with controls, but significantly increased after unloading. In contrast, sarcoplasmic ubiquitin protein was increased in CHF but significantly decreased after unloading, and both variables were inversely correlated. Cardiomyocyte 20S proteasome expression correlated inversely with cell size, mean DNA content, and cyclin D1, whereas ubiquitin protein expression was positively correlated with these parameters. The 20S proteasome plasma concentration was significantly increased after unloading. CONCLUSIONS: Our data indicate that: (1) the UPS is depressed in CHF; and (2) this is reversed by ventricular unloading and associated with decreased cardiomyocyte hypertrophy, mean DNA content, and cell cycle regulatory proteins. The findings support the view that the UPS is involved in both the pathogenesis of cardiac hypertrophy and "reverse cardiac remodeling" after ventricular unloading.

[ARDS--pulmonary repair and therapeutic options]. / Das akute Lungenversagen--Pulmonale Reparatur und therapeutische Optionen.

The acute respiratory distress syndrome (ARDS) is characterized by inflammation evoked pulmonary edema, hyaline membranes, diffuse endothelial and epithelial injury, and fibrosis. For survival to occur lung repair is required. This review explores recent advances in the field of fibroproliferation with emphasis on cellular and soluble factors, mechanisms involved in lung repair, and genetic factors which influence severity and survival in ARDS.

Alveolar extracellular 20S proteasome in patients with acute respiratory distress syndrome.

RATIONALE: Repair mechanisms resulting in alveolar protein degradation in acute respiratory distress syndrome (ARDS) are largely unknown. OBJECTIVES: To test whether the 20S proteasome is present and functional in the alveolar space in patients with ARDS. METHODS: Proteasome antigenic concentration in bronchoalveolar lavage (BAL) supernatants was measured by ELISA in patients with ARDS (n = 64), acute lung injury (ALI) (n = 8), sarcoidosis (n = 13), and in healthy subjects (n = 8). Cleavage of specific fluorogenic substrates (+/-epoxomicin), I(125) albumin degradation rate, and gel filtration were used to quantify and characterize proteasomal activity. The presence of proteasomes was confirmed independently by electron microscopic techniques. MEASUREMENTS AND MAIN RESULTS: Proteasome concentrations in patients with ARDS were markedly increased (1,069 +/- 1,194 ng/ml) in comparison to healthy subjects (60.8 +/- 49.8; P < 0.001), ALI (154 +/- 43; P = 0.006), and sarcoidosis (97.6 +/- 42.2; P = 0.037). All fluorogenic substrates were hydrolyzed (Suc-LLVY-AMC, 3.6 +/- 8.8 pkat/mg; BZ-VGR-AMC, 1.8 +/- 3.1; Suc-LLE-AMC, 1 +/- 1.7) by BAL supernatants of patients with ARDS, with inhibition by epoxomicin (P = 0.0001), and the majority of proteolytic activity was detected in BAL supernatant. Maximum hydrolyzing activity occurred at 660 kD and 20S proteasome was seen microscopically after purification and being released by pneumocytes type II. Proteasomal activity and albumin degradation rate in patients with ARDS were approximately 17-fold lower than in healthy subjects. Proteasomal activity in normal BAL was inhibited by BAL aliquots from patients with ARDS but not by denatured BAL, and returned to normal by purification. CONCLUSIONS: For the first time, we identified extracellular, biologically active 20S proteasome in the alveolar space of patients with ARDS in concentrations much higher than in normal subjects or in those with ALI.

Extracellular proteasome in the human alveolar space: a new housekeeping enzyme?

We hypothesized that 20S proteasome is present and functional in the extracellular alveolar space in humans. Proteasomal activity was measured in bronchoalveolar lavage (BAL) supernatant from eight humans using specific proteasomal fluorogenic substrates and I(125)-albumin with and without specific proteasome inhibitors. Furthermore, gelfiltration, Western blot technique, and mass spectrometry were applied for proteasome characterization. All proteasomal fluorogenic substrates were hydrolyzed by BAL supernatant, with hydrolysis inhibited by epoxomicin (P = 0.024) and other proteasome inhibitors as well. E64, a lysosomal inhibitor, did not inhibit enzyme activity. The majority of proteolytic activity was detected in BAL supernatant rather than in the cell pellet. No correlation was found between proteasomal hydrolysis in BAL supernatant and lactate dehydrogenase activity, the total cell count in the cell pellet, and the fraction of avital cells in the cell pellet, ruling out cell lysis as a major source of proteasomal activity. Gelfiltration revealed hydrolyzing activity in the supernatant at 660 kDa and proteasome core proteins after analysis by ESI-QqTOF mass spectrometry. Furthermore, Western blots using a polyclonal antibody against proteasomal alpha-/beta-subunits detected proteasomal proteins in the typical 20- to 30-kDa range in BAL supernatant. Incubation of BAL supernatant with I(125)-albumin showed a high mean cleavage rate (101.8 microg/ml x h lavage +/- 46 SD) that was inhibited by epoxomicin (P = 0.013) and was ATP and ubiquitin independent. We identified for the first time extracellular, biologically active, ATP- and ubiquitin-independent 20S proteasome in the human alveolar space, with a high albumin cleavage rate. Possibly, the proteasome assists in maintenance of a low intra-alveolar oncotic pressure and/or alveolar protein degradation.