Estimation of Mycophenolic Acid Exposure in Heart Transplant Recipients by Population Pharmacokinetic and Limited Sampling Strategies.

Purpose: The aim of this study is i) to establish a strategy to estimate the area under the curve of the dosing interval (AUC0-12h) of mycophenolic acid (MPA) in the heart transplant recipients and ii) to find the covariates that significantly affect the pharmacokinetics of MPA exposure. Methods: This single-center, prospective, open-label, observational study was conducted in 91 adult heart transplant recipients orally taking mycophenolate mofetil dispersible tablets. Samples collected intensively and sparsely were analyzed by the enzyme-multiplied immunoassay technique, and all the data were used in PPK modeling. Potential covariates were tested stepwise. The goodness-of-fit plots, the normalized prediction distribution error, and prediction-corrected visual predictive check were used for model evaluation. Optimal sampling times by ED-optimal strategy and multilinear regression (MLR) were analyzed based on the simulated data by the final PPK model. Moreover, using intensive data from 14 patients, the accuracy of AUC0-12h estimation was evaluated by Passing-Bablok regression analysis and Bland-Alman plots for both the PPK model and MLR equation. Results: A two-compartment model with first-order absorption and elimination with a lag time was chosen as the structure model. Co-medication of proton pump inhibitors (PPIs), estimated glomerular filtration rate (eGFR), and albumin (ALB) were found to significantly affect bioavailability (F), clearance of central compartment (CL/F), and the distribution volume of the central compartment (V2/F), respectively. Co-medication of PPIs decreased F by 27.6%. When eGFR decreased by 30 ml/min/1.73 m2, CL/F decreased by 23.7%. However, the impact of ALB on V2/F was limited to MPA exposure. The final model showed an adequate fitness of the data. The optimal sampling design was pre-dose and 1 and 4 h post-dose for pharmacokinetic estimation. The best-fit linear equation was finally established as follows: AUC0-12h = 3.539 × C0 + 0.288 × C0.5 + 1.349 × C1 + 6.773 × C4.5. Conclusion: A PPK model was established with three covariates in heart transplant patients. Co-medication of PPIs and eGFR had a remarkable impact on AUC0-12h of MPA. A linear equation was also concluded with four time points as an alternative way to estimate AUC0-12h for MPA.

PGAM1 deficiency ameliorates myocardial infarction remodeling by targeting TGF-ß via the suppression of inflammation, apoptosis and fibrosis.

Myocardial ischemia-reperfusion (MIR) represents critical challenge for the treatment of acute myocardial infarction diseases. Presently, identifying the molecular basis revealing MIR progression is scientifically essential and may provide effective therapeutic strategies. Phosphoglycerate mutase 1 (PGAM1) is a key aerobic glycolysis enzyme, and exhibits critical role in mediating several biological events, such as energy production and inflammation. However, whether PGAM1 can affect MIR is unknown. Here we showed that PGAM1 levels were increased in murine ischemic hearts. Mice with cardiac knockout of PGAM1 were resistant to MIR-induced heart injury, evidenced by the markedly reduced infarct volume, improved cardiac function and histological alterations in cardiac sections. In addition, inflammatory response, apoptosis and fibrosis in hearts of mice with MIR operation were significantly alleviated by the cardiac deletion of PGAM1. Mechanistically, the activation of nuclear transcription factor κB (NF-κB), p38, c-Jun NH2-terminal kinase (JNK) and transforming growth factor ß (TGF-ß) signaling pathways were effectively abrogated in MI-operated mice with specific knockout of PGAM1 in hearts. The potential of PGAM1 suppression to inhibit inflammatory response, apoptosis and fibrosis were verified in the isolated cardiomyocytes and fibroblasts treated with oxygen-glucose deprivation reperfusion (OGDR) and TGF-ß, respectively. Importantly, PGAM1 directly interacted with TGF-ß to subsequently mediate inflammation, apoptosis and collagen accumulation, thereby achieving its anti-MIR action. Collectively, these findings demonstrated that PGAM1 was a positive regulator of myocardial infarction remodeling due to its promotional modulation of TGF-ß signaling, indicating that PGAM1 may be a promising therapeutic target for MIR treatment.

Roles of Reactive Oxygen Species in Cardiac Differentiation, Reprogramming, and Regenerative Therapies.

Reactive oxygen species (ROS) have been implicated in mechanisms of heart development and regenerative therapies such as the use of pluripotent stem cells. The roles of ROS mediating cell fate are dependent on the intensity of stimuli, cellular context, and metabolic status. ROS mainly act through several targets (such as kinases and transcription factors) and have diverse roles in different stages of cardiac differentiation, proliferation, and maturation. Therefore, further detailed investigation and characterization of redox signaling will help the understanding of the molecular mechanisms of ROS during different cellular processes and enable the design of targeted strategies to foster cardiac regeneration and functional recovery. In this review, we focus on the roles of ROS in cardiac differentiation as well as transdifferentiation (direct reprogramming). The potential mechanisms are discussed in regard to ROS generation pathways and regulation of downstream targets. Further methodological optimization is required for translational research in order to robustly enhance the generation efficiency of cardiac myocytes through metabolic modulations. Additionally, we highlight the deleterious effect of the host's ROS on graft (donor) cells in a paracrine manner during stem cell-based implantation. This knowledge is important for the development of antioxidant strategies to enhance cell survival and engraftment of tissue engineering-based technologies. Thus, proper timing and level of ROS generation after a myocardial injury need to be tailored to ensure the maximal efficacy of regenerative therapies and avoid undesired damage.

[Preservation with high-pressure carbon monoxide better protects ex vivo rabbit heart function than conventional cardioplegic solution preservation].

OBJECTIVE: To investigate the protective effect of high-pressure carbon monoxide for preservation of ex vivo rabbit heart graft in comparison with the conventional HTK cardioplegic solution preservation. METHODS: Heart grafts isolated from 85 New Zealand rabbits were randomly divided into Naive group (n=5), HTK group (n=40) and CO group (n=40). The grafts underwent no preservation procedures in Naive group, preserved at 4 degrees celsius; in HTK cardioplegic solution in HTK group, and preserved at 4 degrees celsius; in a high-pressure tank (PO2: PCO=3200 hPa: 800 hPa) in CO group with Krebs-Henseleit solution perfusion but without cardioplegic solution. After preservation for 2, 4, 6, 8, 10, 14, 18, and 24 h, 5 grafts from the two preservation groups were perfused for 30 min with a modified Langendorff apparatus and examined for left ventricular systolic pressure (LVSP), left ventricular diastolic pressure (LVDP), arrhythmia score (AS), myocardial ultrestructure, and cardiac enzyme profiles. RESULTS: After preservation for 6 to 24 h, the cardiac enzyme profiles and systolic and diastolic functions were significantly better in CO group than in HTK group, but these differences were not obvious between the two groups after graft preservation for 2 to 4 h. Significant changes in the myocardial ultrastructures occurred in the isolated hearts after a 24-h preservation in both CO and HTK groups, but the myocardial damages were milder in CO group. CONCLUSION: Preservation using high-pressure carbon monoxide can better protect isolated rabbit heart graft than the conventional HTK preservation approach especially for prolonged graft preservation.

Hybrid coronary revascularization versus coronary artery bypass grafting for multivessel coronary artery disease: systematic review and meta-analysis.

BACKGROUND: The concept of hybrid coronary revascularization (HCR) combines the left internal mammary artery (LIMA)-left anterior descending (LAD) graft and percutaneous coronary intervention (PCI) to non-LAD vessels. Multiple comparative studies have evaluated the safety and feasibility of HCR and coronary artery bypass grafting (CABG) for multivessel coronary artery disease (MCAD). However, the sample size of each study was small, and evidences based on single-institutional experience. The purpose of this meta-analysis was to compare the short-term outcomes of HCR with those of CABG for MCAD. METHOD: PubMed, EMBASE and Cochrane Library databases, as well as conference proceedings, were searched for eligible studies published up to March 2014. We calculated summary odds ratios (OR) for primary endpoints (death, stroke; myocardial infarction (MI); target vessel revascularization (TVR); major adverse cardiac or cerebrovascular events (MACCEs)) and secondary endpoints (atrial fibrillation (AF); renal failure; length of stay in the intensive care unit (LoS in ICU); length of stay in hospital (LoS in hospital); red blood cell (RBC) transfusion). Data from 6176 participants were derived from ten cohort studies. RESULTS: HCR was non-inferior to CABG in terms of MACCEs during hospitalization (odds ratio (OR), 0.68, 95% confidence interval (CI), 0.34-1.33)and at one-year follow-up(0.32, 0.05-1.89) , and no significant difference was found between HCR and CABG groups in in-hospital and one-year follow-up outcomes of death, MI, stroke, the prevalence of AF and renal failure, whereas HCR was associated with a lower requirement of RBC transfusion and shorter LoS in ICU and LoS in hospital than CABG (weighted mean difference (WMD) -1.25, 95% CI, -1.62 to -0.88; -17.47, -31.01 to -3.93; -1.77, -3.07 to -0.46; respectively). CONCLUSION: Our meta-analysis indicates that HCR is feasible, safe and effective for the treatment of MCAD, with similar in-hospital and one-year follow-up outcome, significantly lower requirement of RBC transfusion, and faster recovery compared with CABG.

Pericardiectomy for constrictive pericarditis: single-center experience in China.

OBJECTIVE: Pericardiectomy is associated with a high prevalence of morbidity and mortality. We evaluated the predictors of in-hospital complications and outcome for pericardiectomy procedure for patients with constrictive pericarditis (CP) in a single-center in China. METHODS: One-hundred sixty-five patients who underwent pericardiectomy for CP between January 1990 and December 2012 at our hospital were evaluated. RESULTS: The mean age of the study cohort was 36.79 ± 18.52 years. The approach was through a median sternotomy in 91.5% of patients. Cardiopulmonary bypass was used in 14.5% (24/165 patients). Unadjusted rates of mortality and complication were approximately 5.4% and 23%, respectively. The main cause of death was severe low cardiac output syndrome. Major complications were postoperative low cardiac output syndrome, reoperation for bleeding, pneumonia, mediastinitis, chylothorax and cerebral infarction. One-year survival was 92%. One-year follow-up revealed that New York Heart Association functional class III or IV, age, intraoperative use of cardiac pulmonary bypass and hemodialysis were associated with increased mortality and morbidity. CONCLUSIONS: Total pericardiectomy is associated with lower perioperative and late mortality, and the extent of pericardial resection should be decided according to individual conditions. Perioperative management and complete release of the thickened pericardium of the left ventricle should prevent postoperative complications.

[Early surgical outcomes of coronary heart disease with severe ischemic mitral regurgitation].

OBJECTIVE: To summarize the experience with surgical treatment of coronary artery disease with severe ischemic mitral valve regurgitation (IMR). METHODS: From January 2006 to December 2009, 45 patients (35 males, 10 females aged 32-74 years) with the diagnosis of coronary artery disease complicated by IMR underwent coronary artery bypass grafting (CABG) combined with mitral valve plasty (MVP, 24 cases) or mitral valve replacement (MVR, 21 cases). RESULTS: Perioperative deaths occurred in 2 cases due to multiple organ failure (MOF). Echocardiography showed a significant reduction of the mitral regurgitation area (from 11.80∓2.45 cm(2) to 2.83∓0.98 cm(2), t=22.80, P=0.00) after CABG combined with mitral valve surgery, with also significantly reduced postoperative left ventricular end diastolic diameter (LVEDD) (from 57.61∓10.06 mm to 51.84∓8.98 mm, t=2.85, P=0.005). No significant difference was detected in the left ventricular ejection fraction after the operation [(52.7∓15.4)% vs (53.2∓13.2)%, t=0.16, P=0.87)]. CONCLUSIONS: CABG combined with mitral valve surgery can improve early postoperative left ventricular function in patients with ischemic coronary heart disease complicated by severe mitral regurgitation, but further follow-up study is still needed for evaluation of the long-term results.

[Early and mid-term results after 17 mm St Jude Regent mechanical valve replacement in 44 patients with small aortic root].

OBJECTIVE: To analyze the changes in the cardiac function after St. Jude Regent mechanical valve replacement and assess the prosthesis-patient matching. METHODS: From October 2007 to March 2009, 44 patients received implantation of 17 mm St. Jude aortic prostheses in our hospital. The patients were followed up for clinical symptoms, signs, electrocardiogram (ECG), echocardiogram and cardiac functions, and the results were compared with those of randomly selected 44 patients receiving 21 mm St. Jude aortic prostheses. RESULTS: In 17 mm St Jude Medica Regent valve group, 8 patients presented with ECG ST segment changes, 3 complained of chest tightness, 3 had occasional chest pain and discomfort, and 8 had grade II and 4 grade III cardiac function. In 21 mm St Jude Medical Regent valve group, 6 patients had ECG ST segment changes, 2 complained of chest tightness, 2 reported occasional chest pain and discomfort, 11 had grade II and 2 grade III cardiac function. No significant differences were found in these indices between the two groups (P=0.32). Compared with those before operation, the two groups showed significant improvements in the left ventricular end-diastolic diameter, left ventricular posterior wall thickness, left ventricular mass index, and aortic pressure gradient (P<0.05). A significant increase in the left ventricular ejection fraction occurred 6-12 months after operation, but without statistical difference between the two groups (P>0.05). CONCLUSION: For underweight patients (<60 kg) and those with small body surface area (<1.6 cm(2)), 17 mm St. Jude Medical Regent valve prosthesis may produce good therapeutic effect, and some indices are even close to those after placement of 21 mm St. Jude Medical Regent valve prosthesis. No obvious prosthesis-patient mismatch occurs after the placement of the 17 mm valve prosthesis and aortic valve ring expansion is not necessary.

[Surgical treatment of 128 cases of constrictive pericarditis].

OBJECTIVE: To summarize the experience with surgical treatment of constrictive pericarditis. METHODS: A retrospective analysis of the post-operative clinical data was conducted in 128 surgical patients with chronic constrictive pericarditis. RESULTS: Two early postoperative death occurred in this group due to severe low cardiac output syndrome, with the mortality rate of 1.57%. The postoperative complications included low cardiac output syndrome (13.2%), arrhythmia (7.02%), acute renal insufficiency (3.9%), respiratory insufficiency (3.1%), wound infection (2.3%), postoperative chest bleeding (1.6%) and cerebral infarction (0.78%). Relapse occurred in one case because of incomplete pericardial resection. CONCLUSIONS: Constrictive pericarditis should be confirmed as soon as possible with actively surgery, and the extent of pericardial resection should be decided according to the individual conditions. Complete untethering of the diseased pericardium should be performed with active prevention of postoperative complications.

[Transepicardial autologous transplantation of bone marrow mononuclear cells for acute myocardial infarction].

OBJECTIVE: To test the effect of intramyocardial injection of autologous bone marrow mononuclear cells (MNCs) in improving the cardiac function and myocardial revascularization in miniswine models of myocardial infarction. METHODS: The miniswine models of myocardial infarction established by ligation of the anterior descending coronary artery were divided into 3 groups including a control and two MNC injection groups. Autologous bone marrow MNCs were injected via the epicardium into the infarcted area in the latter two groups at 1 and 2 weeks after the infarction, respectively. The ventricular segmental wall motion was evaluated after the treatment, and the infarcted myocardium observed with immunohistochemistry on frozen sections. RESULTS: The left ventricular segmental wall motion differed significantly between the control and the MNC injection groups at 1 and 2 months after the treatment. CM-DiI-positive cells were detected in the infarcted myocardium where MNCs were implanted. CONCLUSION: Intramyocardial injection of autologous bone marrow MNCs improves the infarcted ventricular segmental wall motion, and significantly increases the number of blood vessels in the infracted area. The transplanted cells can be integrated into the vascular walls of the capillaries and arterioles and differentiate into cardiomyocytes.