Comparison of modified Del Nido and Custodiol® cardioplegia in minimally invasive mitral valve surgery.

OBJECTIVES: In this study, we evaluated if modified Del Nido cardioplegia delivers comparable cardiac protection in comparison to Custodiol® in patients undergoing isolated minimally invasive mitral valve repair. METHODS: From January 2018 to October 2021, all patients undergoing non-emergent isolated minimally invasive mitral valve repair were included in this study. The cardioplegia was chosen at the surgeons' discretion. The primary end points of this study were peak postoperative cardiac enzyme levels. Secondary end points were in-hospital mortality, hospital stay, occurrence of cardiac arrhythmias, pacemaker implantations, postoperative lactate and sodium levels and postoperative incidence of renal failure requiring dialysis. RESULTS: A total of 355 patients were included in this study. The mean age of patients was 57. After propensity score matching, a total of 156 pairs were identified. There was no difference in cross-clamp time between both groups. Postoperative creatine kinase levels were higher in patients receiving Custodiol on the 1st and 2nd postoperative days. Creatine kinase isoenzyme MB levels were higher in patients receiving Custodiol on the 2nd postoperative day (0.5 ± 0.2 vs 0.4 ± 0.1 µmol/l s; P < 0.001). Postoperative Troponin T concentrations were similar between both groups. Maximum lactate concentrations were higher in patients receiving Custodiol on the day of surgery (2.4 ± 1.9 vs 2.0 ± 1.1 mmol/l; P = 0.04). The overall hospital stay was longer in patients receiving Del Nido cardioplegia (10.6 ± 3.2 vs 8 ± 4.1 days; P < 0.01). CONCLUSIONS: Modified Del Nido cardioplegia based on Ionosteril® solution offers equivalent protection compared to Custodiol for isolated minimally invasive mitral valve repair.

Pre-Implant Immune Status is Associated with Infection Risk After Left Ventricular Assist Device Implantation.

Purpose: Infection is the most common complication after left ventricular assist device (LVAD) implantation. The immune status of LVAD patients is relevant for the incidence and severity of infection, but it is unknown if there is a predisposing immune status prior to LVAD implantation that contributes to an increased risk for infection in the post-implant period. We analyzed the pre-LVAD immune status in patients with infection within 3 months after LVAD implantation in comparison to infection-free patients. Patients and Methods: Fifty-four consecutive LVAD patients were included in this study. According to their infectious history in the first 3 months after LVAD implantation, these patients were grouped into an infection (n=23) and an infection-free group (n=31). Pre-LVAD blood samples were obtained for flow cytometric analysis of immunological parameters including B cells, subsets of T, dendritic and natural killer cells. Patient-specific, clinical and laboratory data were recorded. Results: Blood count analysis prior to LVAD implantation showed comparable counts of erythrocytes (p=0.19), platelets (p=0.33) and leukocytes (p=0.50) between patients with infection and infection-free patients in the post-implant period. Patients with infection in the first 3 months after LVAD implantation had lower concentrations of lymphocytes (p=0.02). Forty percent of the patients with infection showed more often pre-LVAD neutrophil-to-lymphocyte ratios (NLR) >7 than patients without infection in the first 3 months after LVAD implantation (14%, p=0.05). Patients with infection already had lower percentages of CD3+ T cells (p=0.03), CD19+ B cells (p<0.01), BDCA2+ pDCs (p=0.03) and BDCA4+ plasmacytoid DCs (pDCs) (p=0.05) prior to LVAD implantation than infection-free patients. Conclusion: Our results demonstrated that patients with infection in the early post-implant period showed lower concentrations of lymphocytes, especially of CD3+ T cells and CD19+ B cells, decreased percentages of BDCA2+ and BDCA4+ pDCs, and had more often NLRs >7 indicating moderate-to-severe inflammation. Thus, we identified specific immunological changes pre-LVAD that could help to identify patients at risk for infection in the early post-implant period.

Left ventricular fibrosis and CMR tissue characterization of papillary muscles in mitral valve prolapse patients.

PURPOSE: Mitral valve prolapse (MVP) is associated with left ventricle (LV) fibrosis, including the papillary muscles (PM), which is in turn linked to malignant arrhythmias. This study aims to evaluate comprehensive tissue characterization of the PM by cardiovascular magnetic resonance (CMR) imaging and its association with LV fibrosis observed by intraoperative biopsies. METHODS: MVP patients with indication for surgery due to severe mitral regurgitation (n = 19) underwent a preoperative CMR with characterization of the PM: dark-appearance on cine, T1 mapping, conventional bright blood (BB) and dark blood (DB) late gadolinium enhancement (LGE). CMR T1 mapping was performed on 21 healthy volunteers as controls. LV inferobasal myocardial biopsies were obtained in MVP patients and compared to CMR findings. RESULTS: MVP patients (54 ± 10 years old, 14 male) had a dark-appearance of the PM with higher native T1 and extracellular volume (ECV) values compared with healthy volunteers (1096 ± 78ms vs. 994 ± 54ms and 33.9 ± 5.6% vs. 25.9 ± 3.1%, respectively, p < 0.001). Seventeen MVP patients (89.5%) had fibrosis by biopsy. BB-LGE + in LV and PM was identified in 5 (26.3%) patients, while DB-LGE + was observed in LV in 9 (47.4%) and in PM in 15 (78.9%) patients. DB-LGE + in PM was the only technique that showed no difference with detection of LV fibrosis by biopsy. Posteromedial PM was more frequently affected than the anterolateral (73.7% vs. 36.8%, p = 0.039) and correlated with biopsy-proven LV fibrosis (Rho 0.529, p = 0.029). CONCLUSIONS: CMR imaging in MVP patients referred for surgery shows a dark-appearance of the PM with higher T1 and ECV values compared with healthy volunteers. The presence of a positive DB-LGE at the posteromedial PM by CMR may serve as a better predictor of biopsy-proven LV inferobasal fibrosis than conventional CMR techniques.

Body mass index-dependent immunological profile changes after left ventricular assist device implantation.

Purpose: Infection is a common complication following left ventricular assist device (LVAD) implantation. Patients with obesity are particularly at risk due to their high percentage of adipose tissue and the resulting chronic inflammatory state and resulting immunological changes. This study investigated changes of immunological parameters in relation to body mass index (BMI) during the first year after LVAD implantation. Methods: Blood samples were obtained prior to LVAD implantation and at 3 (1st FU), 6 (2nd FU) and 12 mo (3rd FU) after LVAD implantation. Patients were divided into three groups (normal weight: BMI of 18.5-24.9 kg/m2; n=12; pre-obesity: 25.0-29.9 kg/m2; n=15; obesity: ≥ 30.0 kg/m2; n=17) based on their BMI at the time of LVAD implantation. Flow cytometric analyses for CD4+ and CD8+ T cells, regulatory T cells (Tregs), B cells as well as dendritic cells (DCs) were performed. Results: After LVAD implantation, obese patients (0.51 ± 0.20%) showed a higher proportion of overall DCs than normal-weight (0.28 ± 0.10%) and pre-obese patients (0.32 ± 0.11%, p<0.01) at 3rd FU. The proportion of BDCA3+ myeloid DCs was lower in obese patients (64.3 ± 26.5%) compared to normal-weight patients (82.7 ± 10.0%, pnormal-weight vs. obesity=0.05) at 2nd FU after LVAD implantation. The analysis of BDCA4+ plasmacytoid DCs revealed a reduced proportion in pre-obese (21.1 ± 9.8%, pnormal-weight vs. pre-obesity=0.01) and obese patients (23.7 ± 10.6%, pnormal-weight vs. obesity=0.05) compared to normal-weight patients (33.1 ± 8.2%) in the 1st FU. T cell analysis showed that CD4+ T cells of obese patients (62.4 ± 9.0%) significantly increased in comparison to pre-obese patients (52.7 ± 10.0%, ppre-obesity vs. obesity=0.05) and CD8+ T cells were lower in obese patients (31.8 ± 8.5%) than in normal-weight patients (42.4 ± 14.2%; pnormal-weight vs. obesity=0.04) at the 3rd FU. Furthermore, we observed significantly reduced proportions of Tregs in pre-obese patients compared to normal-weight and obese patients at 2nd FU (p=0.02) and 3rd FU (p=0.01) after LVAD implantation. Conclusion: This study reported changes of the innate and adaptive immune system of pre-obese and obese compared to normal-weight patients one year after LVAD implantation. DCs and their subsets, CD8+ T cells and Tregs were affected immune cell populations that indicate immunological changes which might increase the incidence of postoperative infection.

Health status analysis is comparable in HM3 patients with different preoperative grades of mitral regurgitation.

BACKGROUND: The guidelines for mechanical circulatory support of the International Society for Heart and Lung Transplantation do not recommend the routine replacement or repair of the mitral valve at the time point of left ventricular assist device (LVAD) implantation. We investigated different parameters of health status including exercise capacity, anxiety and depression after LVAD implantation in patients with different preoperative grades of mitral regurgitation (MR). METHODS: A single-center analysis of health status was performed including 45 patients with HeartMate 3 (HM 3) implantation using the 12-items Short Form Health Survey (SF-12) and the Hospital Anxiety and Depression Score (HADS) questionnaires. The study groups were classified according to echocardiographically defined preoperative grade of MR. The group without severe MR comprised 33 patients; the group with severe MR comprised 12 patients. RESULTS: Demographic and preclinical characteristics as well as LVAD complications such as thrombosis and bleeding events were comparable between LVAD patients with severe and not severe MR (p > 0.05). Severe MR resolved in all patients after LVAD implantation and improved to moderate, mild or no MR in both groups in a period ranging from 6 months until 2 years. The analyses of SF-12 questionnaire revealed that the physical (p = 0.44) and mental health (p = 0.64) was comparable. The grade of anxiety (p = 0.34) and depression (p = 0.44) was comparable between the groups. Exercise capacity measured by the 6 min walk test correlated positively with the SF-12-determined physical health (p < 0.01, r = 0.518) and negatively with the HADS anxiety (p = 0.01, r = -0.399) and depression (p < 0.01, r = -0.570) scores. CONCLUSIONS: Our data showed that the health status is comparable in HM 3 patients with different preoperative MR severities in the post-LVAD period. Preoperative severe MR resolves in the majority of patients early after LVAD implantation and is not associated with concomitant mitral valve repair or replacement at the time of LVAD implantation.

Left Ventricular Fibrosis and CMR Tissue Characterization of Papillary Muscles in Mitral Valve Prolapse Patients.

Purpose: Mitral valve prolapse (MVP) is associated with left ventricle (LV) fibrosis, including the papillary muscles (PM), which is in turn linked to malignant arrhythmias. This study aims to evaluate comprehensive tissue characterization of the PM by cardiovascular magnetic resonance (CMR) imaging and its association with LV fibrosis observed by intraoperative biopsies. Methods: MVP patients with indication for surgery due to severe mitral regurgitation (n=19) underwent a preoperative CMR with characterization of the PM: dark-appearance on cine, T1 mapping, conventional bright blood (BB) and dark blood (DB) late gadolinium enhancement (LGE). CMR T1 mapping was performed on 21 healthy volunteers as controls. LV inferobasal myocardial biopsies were obtained in MVP patients and compared to CMR findings. Results: MVP patients (54±10 years old, 14 male) had a dark-appearance of the PM with higher native T1 and extracellular volume (ECV) values compared with healthy volunteers (1096±78ms vs 994±54ms and 33.9±5.6% vs 25.9±3.1%, respectively, p<0.001). Seventeen MVP patients (89.5%) had fibrosis by biopsy. BB-LGE+ in LV and PM was identified in 5 (26.3%) patients, while DB-LGE+ was observed in LV in 9 (47.4%) and in PM in 15 (78.9%) patients. DB-LGE+ in PM was the only technique that showed no difference with detection of LV fibrosis by biopsy. Posteromedial PM was more frequently affected than the anterolateral (73.7% vs 36.8%, p=0.039) and correlated with biopsy-proven LV fibrosis (Rho 0.529, p=0.029). Conclusions: CMR imaging in MVP patients referred for surgery shows a dark-appearance of the PM with higher T1 and ECV values compared with healthy volunteers. The presence of a positive DB-LGE at the posteromedial PM by CMR may serve as a better predictor of biopsy-proven LV inferobasal fibrosis than conventional CMR techniques.

The Impact of Obesity on T and NK Cells after LVAD Implantation.

INTRODUCTION: Infections are a major problem after left ventricular assist device (LVAD) implantation that affects morbidity, mortality, and the quality of life. Obesity often increases the risk for infection. In the cohort of LVAD patients, it is unknown if obesity affects the immunological parameters involved in viral defense. Therefore, this study investigated whether overweight or obesity affects immunological parameters such as CD8+ T cells and natural killer (NK) cells. METHODS: Immune cell subsets of CD8+ T cells and NK cells were compared between normal-weight (BMI 18.5-24.9 kg/m2, n = 17), pre-obese (BMI 25.0-29.9 kg/m2, n = 24), and obese (BMI ≥30 kg/m2, n = 27) patients. Cell subsets and cytokine serum levels were quantified prior to LVAD implantation and at 3, 6, and 12 months after LVAD implantation. RESULTS: At the end of the first postoperative year, obese patients (31.8% ± 2.1%) had a lower proportion of CD8+ T cells than normal-weight patients (42.4% ± 4.1%; p = 0.04), and the percentage of CD8+ T cells was negatively correlated with BMI (p = 0.03; r = -0.329). The proportion of circulating NK cells increased after LVAD implantation patients in normal-weight (p = 0.01) and obese patients (p < 0.01). Patients with pre-obesity showed a delayed increase (p < 0.01) 12 months after LVAD implantation. Further, obese patients showed an increase in the percentage of CD57+ NK cells after 6 and 12 months (p = 0.01) of treatment, higher proportions of CD56bright NK cells (p = 0.01), and lower proportions of CD56dim/neg NK cells (p = 0.03) 3 months after LVAD implantation than normal-weight patients. The proportion of CD56bright NK cells positively correlated with BMI (p < 0.01, r = 0.403) 1 year after LVAD implantation. CONCLUSIONS: This study documented that obesity affects CD8+ T cells and subsets of NK cells in patients with LVAD in the first year after LVAD implantation. Lower proportions of CD8+ T cells and CD56dim/neg NK cells and higher proportion of CD56bright NK cells were detected in obese but not in pre-obese and normal-weight LVAD patients during the first year after LVAD implantation. The induced immunological imbalance and phenotypic changes of T and NK cells may influence viral and bacterial immunoreactivity.

Histopathological insights into mitral valve prolapse-induced fibrosis.

Mitral valve prolapse (MVP) is a cardiac valve disease that not only affects the mitral valve (MV), provoking mitral regurgitation, but also leads to maladaptive structural changes in the heart. Such structural changes include the formation of left ventricular (LV) regionalized fibrosis, especially affecting the papillary muscles and inferobasal LV wall. The occurrence of regional fibrosis in MVP patients is hypothesized to be a consequence of increased mechanical stress on the papillary muscles and surrounding myocardium during systole and altered mitral annular motion. These mechanisms appear to induce fibrosis in valve-linked regions, independent of volume-overload remodeling effects of mitral regurgitation. In clinical practice, quantification of myocardial fibrosis is performed with cardiovascular magnetic resonance (CMR) imaging, even though CMR has sensitivity limitations in detecting myocardial fibrosis, especially in detecting interstitial fibrosis. Regional LV fibrosis is clinically relevant because even in the absence of mitral regurgitation, it has been associated with ventricular arrhythmias and sudden cardiac death in MVP patients. Myocardial fibrosis may also be associated with LV dysfunction following MV surgery. The current article provides an overview of current histopathological studies investigating LV fibrosis and remodeling in MVP patients. In addition, we elucidate the ability of histopathological studies to quantify fibrotic remodeling in MVP and gain deeper understanding of the pathophysiological processes. Furthermore, molecular changes such as alterations in collagen expression in MVP patients are reviewed.

The Glycoprotein (GP)Ib-IX-V Complex on Platelets: GPIbα Protein Expression Is Reduced in HeartMate 3 Patients with Bleeding Complications within the First 3 Months.

Non-surgical bleeding (NSB) remains the most critical complication in patients under left ventricular assist device (LVAD) support. It is well known that blood exposed to high shear stress results in platelet dysfunction. Compared to patients without NSB, decreased surface expression of platelet receptor GPIbα was observed in LVAD patients with NSB. In this study, we aimed to compare the expression level of glycoprotein (GP)Ib-IX-V platelet receptor complex in HeartMate 3 (HM 3) patients with and without bleeding complications to investigate the alterations of the platelet transcriptomic profile on platelet damage and increased bleeding risk. Blood samples were obtained from HM 3 patients with NSB (bleeder group, n = 27) and without NSB (non-bleeder group, n = 55). The bleeder group was further divided into patients with early NSB (bleeder ≤ 3 mo, n = 19) and patients with late NSB (bleeder > 3 mo, n = 8). The mRNA and protein expression of GPIbα, GPIX and GPV were quantified for each patient. Non-bleeder, bleeder ≤ 3 mo and bleeder > 3 mo were comparable regarding the mRNA expression of GPIbα, GPIX and GPV (p > 0.05). The protein analysis revealed a significantly reduced expression level of the main receptor subunit GPIbα in bleeders ≤ 3 mo (p = 0.04). We suggest that the observed reduction of platelet receptor GPIbα protein expression in patients who experienced their first bleeding event within 3 months after LVAD implantation may influence platelet physiology. The alterations of functional GPIbα potentially reduce the platelet adhesion capacities, which may lead to an impaired hemostatic process and the elevated propensity of bleeding in HM 3 patients.

Myostatin/AKT/FOXO Signaling Is Altered in Human Non-Ischemic Dilated Cardiomyopathy.

Disturbances in the ubiquitin proteasome system, and especially changes of the E3 ligases, are subjects of interest when searching for causes and therapies for cardiomyopathies. The aim of this study was to clarify whether the myostatin/AKT/forkhead box O (FOXO) pathway, which regulates the expression of the E3 ligases muscle atrophy F-box gene (MAFbx) and muscle ring-finger protein-1 (MuRF1), is changed in dilated cardiomyopathy of ischemic origin (IDCM) and dilated cardiomyopathy of non-ischemic origin (NIDCM). The mRNA and protein expression of myostatin, AKT, FOXO1, FOXO3, MAFbx and MuRF1 were quantified by real-time polymerase chain reaction and ELISA, respectively, in myocardial tissue from 26 IDCM and 23 NIDCM patients. Septal tissue from 17 patients undergoing Morrow resection served as a control. MAFbx and FOXO1 mRNA and protein expression (all p < 0.05), AKT mRNA (p < 0.01) and myostatin protein expression (p = 0.02) were decreased in NIDCM patients compared to the control group. Apart from decreases of AKT and MAFbx mRNA expression (both p < 0.01), no significant differences were detected in IDCM patients compared to the control group. Our results demonstrate that the myostatin/AKT/FOXO pathway is altered in NIDCM but not in IDCM patients. FOXO1 seems to be an important drug target for regulating the expression of MAFbx in NIDCM patients.

Decreased Platelet Specific Receptor Expression of P-Selectin and GPIIb/IIIa Predict Future Non-Surgical Bleeding in Patients after Left Ventricular Assist Device Implantation.

Non-surgical bleeding (NSB) is one of the major clinical complications in patients under continuous-flow left ventricular assist device (LVAD) support. The increased shear stress leads to an altered platelet receptor composition. Whether these changes increase the risk for NSB is unclear. Thus, we compared the platelet receptor composition of patients with (bleeder group, n = 18) and without NSB (non-bleeder group, n = 18) prior to LVAD implantation. Blood samples were obtained prior to LVAD implantation and after bleeding complications in the post-implant period. Platelet receptor expression of GPIbα, GPIIb/IIIa, P-selectin and CD63 as well as intra-platelet oxidative stress levels were quantified by flow cytometry. Bleeders and non-bleeders were comparable regarding clinical characteristics, von Willebrand factor diagnostics and the aggregation capacity before and after LVAD implantation (p > 0.05). LVAD patients in the bleeder group suffered from gastrointestinal bleeding (33%; n = 6), epistaxis (22%; n = 4), hematuria or hematoma (17%; n = 3, respectively) and cerebral bleeding (11%; n = 2). Prior to LVAD implantation, a restricted surface expression of the platelet receptors P-selectin and GPIIb/IIIa was observed in the bleeder group (P-selectin: 7.2 ± 2.6%; GPIIb/IIIa: 26,900 ± 13,608 U) compared to non-bleeders (P-selectin: 12.4 ± 8.1%, p = 0.02; GPIIb/IIIa: 36,259 ± 9914 U; p = 0.02). We hypothesized that the reduced platelet receptor expression of P-selectin and GPIIb/IIIa prior to LVAD implantation may be linked to LVAD-related NSB.

Long-Term Follow-Up of Mechanical Circulatory Support in Peripartum Cardiomyopathy (PPCM) Refractory to Medical Management: A Multicenter Study.

BACKGROUND: Peripartum cardiomyopathy (PPCM) is a rare, life-threatening form of heart disease, frequently associated with gene alterations and, in some cases, presenting with advanced heart failure. Little is known about ventricular assist device (VAD) implantation in severe PPCM cases. We describe long-term follow-up of PPCM patients who were resistant to medical therapy and received mechanical circulatory support or heart transplant. METHODS AND RESULTS: A total of 13 patients were included with mean follow-up of eight years. Mean age of PPCM onset was 33.7 ± 7.7 years. All patients were initially treated with angiotensin-converting enzyme inhibitors and beta-blockers, and four received bromocriptine. Overall, five patients received VADs (three biventricular, two isolated left ventricular) at median 27 days (range: 3 to 150) following childbirth. Two patients developed drive line infection. Due to the short support time, none of those patients had a stroke or VAD thrombosis. In total, five patients underwent heart transplantation, of which four previously had implanted VADs. Median time to transplantation from PPCM onset was 140 days (range: 43 to 776), and time to transplantation from VAD implantation were 7, 40, 132, and 735 days, respectively. All patients survived until most recent follow up, with the exception of one patient who died following unrelated abdominal surgery two years after PPCM recovery. CONCLUSIONS: In patients with severe, life-threatening PPCM refractory to medical management, mechanical circulatory support with or without heart transplantation is a safe therapeutic option.

Validation of mitral regurgitation reversibility in patients with HeartMate 3 LVAD implantation.

The resolution of functional mitral valve regurgitation (MR) in patients awaiting left ventricular assist device (LVAD) implantation is discussed controversially. The present study analyzed MR and echocardiographic parameters of the third-generation LVAD HeartMate 3 (HM3) over 3 years. Of 135 LVAD patients (with severe MR, n = 33; with none, mild, or moderate MR, n = 102), data of transthoracic echocardiography were included preoperatively to LVAD implantation, up to 1 month postoperatively, and at 1, 2, and 3 years after LVAD implantation. Demographic data and clinical characteristics were collected. Severe MR was reduced immediately after LVAD implantation in all patients. The echocardiographic parameters left ventricular end-diastolic diameter (P < .001), right ventricular end-diastolic diameter (P < .001), tricuspid annular plane systolic excursion (P < .001), and estimated pulmonary artery pressure (P < .001) decreased after HM3 implantation independently from the grade of MR prior to implantation and remained low during the 2 years follow-up period. Following LVAD implantation, right heart failure, ventricular arrhythmias, ischemic stroke as well as pump thrombosis and bleeding events were comparable between the groups. The incidences of death and cardiac death did not differ between the patient groups. Furthermore, the Kaplan-Meier analysis showed that survival was comparable between the groups (P = .073). HM3 implantation decreases preoperative severe MR immediately after LVAD implantation. This effect is long-lasting in most patients and reinforces the LVAD implantation without MR surgery. The complication rates and survival were comparable between patients with and without severe MR.

Everolimus-Induced Immune Effects after Heart Transplantation: A Possible Tool for Clinicians to Monitor Patients at Risk for Transplant Rejection.

BACKGROUND: Patients treated with an inhibitor of the mechanistic target of rapamycin (mTORI) in a calcineurin inhibitor (CNI)-free immunosuppressive regimen after heart transplantation (HTx) show a higher risk for transplant rejection. We developed an immunological monitoring tool that may improve the identification of mTORI-treated patients at risk for rejection. METHODS: Circulating dendritic cells (DCs) and regulatory T cells (Tregs) were analysed in 19 mTORI- and 20 CNI-treated HTx patients by flow cytometry. Principal component and cluster analysis were used to identify patients at risk for transplant rejection. RESULTS: The percentages of total Tregs (p = 0.02) and CD39+ Tregs (p = 0.05) were higher in mTORI-treated patients than in CNI-treated patients. The principal component analysis revealed that BDCA1+, BDCA2+ and BDCA4+ DCs as well as total Tregs could distinguish between non-rejecting and rejecting mTORI-treated patients. Most mTORI-treated rejectors showed higher levels of BDCA2+ and BDCA4+ plasmacytoid DCs and lower levels of BDCA1+ myeloid DCs and Tregs than mTORI non-rejectors. CONCLUSION: An mTORI-based immunosuppressive regimen induced a sufficient, tolerance-promoting reaction in Tregs, but an insufficient, adverse effect in DCs. On the basis of patient-specific immunological profiles, we established a flow cytometry-based monitoring tool that may be helpful in identifying patients at risk for rejection.

Differential Regulation of Myocardial E3 Ligases and Deubiquitinases in Ischemic Heart Failure.

The pathological changes of ubiquitination and deubiquitination following myocardial infarction (MI) and chronic heart failure (CHF) have been sparsely examined. We investigated the expression of muscle-specific E3 ubiquitin ligases and deubiquitinases in MI and CHF. Therefore, mice were assigned to coronary artery ligation for 3 days or 10 weeks as well as for sham operation (each n = 10). Expression of E3 ligases (MAFBX, MURF1, CHIP, ITCH, MDM2) and deubiquitinases (A20, CYLD, UCH-L1, USP14, USP19) was determined. After MI and in CHF, the mRNA expression of MURF1, CHIP and MDM2 (all p < 0.05) was decreased. Protein expression analyses revealed that ITCH expression decreased in CHF (p = 0.01), whereas MDM2 expression increased in MI (p = 0.02) and decreased in CHF (p = 0.02). Except for USP19 mRNA expression that decreased at 3 days and 10 weeks (both p < 0.01), the expression of other deubiquitinases remained unaffected after MI and CHF. The expression of myocardial E3 ligases is differentially regulated following MI, raising the question of whether an upstream regulation exists that is activated by MI for tissue protection or whether the downregulation of E3 ligases enables myocardial hypertrophy following MI.

Relevance and Recommendations for the Application of Cardioplegic Solutions in Cardiopulmonary Bypass Surgery in Pigs.

Cardioplegic solutions play a major role in cardiac surgery due to the fact that they create a silent operating field and protect the myocardium against ischemia and reperfusion injury. For studies on cardioplegic solutions, it is important to compare their effects and to have a valid platform for preclinical testing of new cardioplegic solutions and their additives. Due to the strong anatomical and physiological cardiovascular similarities between pigs and humans, porcine models are suitable for investigating the effects of cardioplegic solutions. This review provides an overview of the results of the application of cardioplegic solutions in adult or pediatric pig models over the past 25 years. The advantages, disadvantages, limitations, and refinement strategies of these models are discussed.

Immune Monitoring Assay for Extracorporeal Photopheresis Treatment Optimization After Heart Transplantation.

Background: Extracorporeal photopheresis (ECP) induces immunological changes that lead to a reduced risk of transplant rejection. The aim of the present study was to determine optimum conditions for ECP treatment by analyzing a variety of tolerance-inducing immune cells to optimize the treatment. Methods: Ten ECP treatments were applied to each of 17 heart-transplant patients from month 3 to month 9 post-HTx. Blood samples were taken at baseline, three times during treatment, and four months after the last ECP treatment. The abundance of subsets of tolerance-inducing regulatory T cells (Tregs) and dendritic cells (DCs) in the samples was determined by flow cytometry. A multivariate statistical model describing the immunological status of rejection-free heart transplanted patients was used to visualize the patient-specific immunological improvement induced by ECP. Results: All BDCA+ DC subsets (BDCA1+ DCs: p < 0.01, BDCA2+ DCs: p < 0.01, BDCA3+ DCs: p < 0.01, BDCA4+ DCs: p < 0.01) as well as total Tregs(p < 0.01) and CD39+ Tregs(p < 0.01) increased during ECP treatment, while CD62L+ Tregs decreased (p < 0.01). The cell surface expression level of BDCA1 (p < 0.01) and BDCA4 (p < 0.01) on DCs as well as of CD120b (p < 0.01) on Tregs increased during the study period, while CD62L expression on Tregs decreased significantly (p = 0.04). The cell surface expression level of BDCA2 (p = 0.47) and BDCA3 (p = 0.22) on DCs as well as of CD39 (p = 0.14) and CD147 (p = 0.08) on Tregs remained constant during the study period. A cluster analysis showed that ECP treatment led to a sustained immunological improvement. Conclusions: We developed an immune monitoring assay for ECP treatment after heart transplantation by analyzing changes in tolerance-inducing immune cells. This assay allowed differentiation of patients who did and did not show immunological improvement. Based on these results, we propose classification criteria that may allow optimization of the duration of ECP treatment.

Cyclosporine A-enhanced cardioplegia preserves mitochondrial basal respiration after ischemic arrest.

BACKGROUND: Mitochondrial permeability transition pore (mPTP) opening plays a crucial role in cell death during ischemia-reperfusion injury (IRI). Cyclosporine A (CsA) inhibits mPTP opening. This study aimed to investigate the effects of CsA treatment during cardioplegia on the mitochondrial function and cardiac IRI. METHODS: Landrace pigs (52.9 ± 3.7 kg) were subjected to midline sternotomy, cardiopulmonary bypass at 34°C and 90 minutes of cardiac arrest. They received either a single shot of standard 4°C cold histidine-tryptophan-α-ketoglutarate (HTK)-Bretschneider solution (n = 11) or HTK-Bretschneider plus 1.2 mg/L CsA (histidine-tryptophan-α-ketoglutarate plus cyclosporine A (HTK/CsA); n = 11). During reperfusion global left-ventricular function was assessed and myocardial biopsies were harvested at baseline, during ischemia and 45 minutes following reperfusion. High-resolution respirometry and hydrogen peroxide production were measured. Immunohistochemical stainings for apoptosis-inducing factor and hypoxia-inducible factor-1α as well as a flow cytometry-based JC-1 mitochondrial membrane potential assay were performed. RESULTS: Hemodynamic parameters were comparable between both groups. The cytochrome C release (HTK: 930.3 ± 804.4 pg/mg, HTK/CsA: 699.7 ± 394.0 pg/mg, p = 0.457) as well as PGC1α content (HTK: 66.7%, HTK/CsA: 33.3%, p = 0.284) was lower in the HTK/CsA group. Respiratory measurements revealed that the oxygen flux under basal respiration was higher in the HTK/CsA group (8.2 ± 1.3 pmol·O2·s-1·mg-1·ww) than in the HTK group (3.8 ± 1.4 pmol·O2·s-1·mg-1·ww, p = 0.045). There were no significant differences regarding histological surrogates of apoptosis and necrosis. CONCLUSIONS: Supplementing cardioplegic solutions with CsA enhances the basal mitochondrial respiration thereby exerting a cardioprotective effect and diminishing IRI-induced damage. CsA seems to preserve mitochondrial function via non-ROS related pathways.

Personalized Therapy for Mycophenolate: Consensus Report by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology.

ABSTRACT: When mycophenolic acid (MPA) was originally marketed for immunosuppressive therapy, fixed doses were recommended by the manufacturer. Awareness of the potential for a more personalized dosing has led to development of methods to estimate MPA area under the curve based on the measurement of drug concentrations in only a few samples. This approach is feasible in the clinical routine and has proven successful in terms of correlation with outcome. However, the search for superior correlates has continued, and numerous studies in search of biomarkers that could better predict the perfect dosage for the individual patient have been published. As it was considered timely for an updated and comprehensive presentation of consensus on the status for personalized treatment with MPA, this report was prepared following an initiative from members of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT). Topics included are the criteria for analytics, methods to estimate exposure including pharmacometrics, the potential influence of pharmacogenetics, development of biomarkers, and the practical aspects of implementation of target concentration intervention. For selected topics with sufficient evidence, such as the application of limited sampling strategies for MPA area under the curve, graded recommendations on target ranges are presented. To provide a comprehensive review, this report also includes updates on the status of potential biomarkers including those which may be promising but with a low level of evidence. In view of the fact that there are very few new immunosuppressive drugs under development for the transplant field, it is likely that MPA will continue to be prescribed on a large scale in the upcoming years. Discontinuation of therapy due to adverse effects is relatively common, increasing the risk for late rejections, which may contribute to graft loss. Therefore, the continued search for innovative methods to better personalize MPA dosage is warranted.

Device-induced platelet dysfunction in patients after left ventricular assist device implantation.

BACKGROUND: Non-surgical bleeding (NSB) is a major complication after left ventricular assist device (LVAD) implantation. It has been reported that non-physiological shear stress caused by LVADs could alter platelet receptor expression, which leads to bleeding disorders caused by coagulation dysfunctions. OBJECTIVES: Because bleeding diathesis could be multifactorial, we focused on the combined characterization of platelet receptor expression patterns and oxidative stress to compare patients with NSB and patients without coagulation disorder in a monocentric, prospective study. METHODS: Blood samples were obtained from LVAD patients with NSB (bleeder group, n = 19) and without NSB (non-bleeder group, n = 20). The platelet receptors platelet endothelial cell adhesion molecule-1 (PECAM-1), glycoprotein (GP)Ibα, P-selectin, CD63, and GPIIb/IIIa, as well as the production of intraplatelet reactive oxygen species (ROS) were quantified by flow cytometry. Aggregation capacity was evaluated by aggregometry. RESULTS: The surface expression level of P-selectin and GPIbα on platelets was decreased in bleeders (P-selectin: 465 ± 72 U; GPIbα: 435 ± 41 U) compared to non-bleeders (P-selectin: 859 ± 115 U, P < .01; GPIbα: 570 ± 49 U, p = .04). Additionally, the mean fluorescence intensity of ADP-stimulated P-selectin and PECAM-1 expressing platelets were reduced in bleeders (P-selectin: 944 ± 84 U; PECAM-1: 6722 ± 419 U) compared to non-bleeders (P-selectin: 1269 ± 130 U, P = .04; PECAM-1: 8542 ± 665 U, P = .03). Bleeders showed a higher amount of ROS formation in platelets (88.0 ± 2.6%) than non-bleeders (81.5 ± 2.1%, P = .05). CONCLUSIONS: These findings suggested that changes of three platelet receptors (GPIbα, P-selectin, and PECAM-1) and elevated oxidative stress may play a role in patients with bleeding complications following LVAD implantation. These results might help to explain the high incidence of spontaneous hemorrhage during LVAD support through an altered platelet function.