In vitro and in vivo evaluation of hypothermia on pharmacokinetics and pharmacodynamics of nimodipine in rabbits.

Objective To investigate the effect of hypothermia on the pharmacokinetics and pharmacodynamics of nimodipine in rabbits using in vivo and in vitro methods. Methods Five healthy New Zealand rabbits received a single dose of nimodipine (0.5 mg/kg) intravenously under normothermic and hypothermic conditions. Doppler ultrasound was used to monitor cerebral blood flow, vascular resistance, and heart rate. In vitro evaluations of protein binding, hepatocyte uptake and intrinsic clearance of liver microsomes at different temperatures were also conducted. Results Plasma concentrations of nimodipine were significantly higher in hypothermia than in normothermia. Nimodipine improved cerebral blood flow under both conditions, but had a longer effective duration during the hypothermic period. Low temperature decreased the intrinsic clearance of liver microsomes, with no change in protein binding or hepatocyte uptake of nimodipine. Conclusion Nimodipine is eliminated at a slower rate during hypothermia than during normothermia, mainly due to the decreased activity of cytochrome P450 enzymes. This results in elevated system exposure with little enhancement in pharmacological effect.

The apelin-APJ pathway exists in cardiomyogenic cells derived from mesenchymal stem cells in vitro and in vivo.

Our previous study demonstrated that apelin level increased significantly after the treatment of intracoronary implantation of bone marrow mononuclear cells (BMMCs), followed by the improvement of cardiac function in patients with severe ischemic heart failure. The present studies both in vivo and in vitro explored whether mesenchymal stem cells derived from bone marrow (BMSCs) activate the apelin-APJ pathway when differentiating into cardiomyogenic cells. Isolated BMSCs from rat femurs and tibias were cultured and expanded for three passages, labeled with DAPI, and treated with 5-azacytidine (5-AZ). BMSCs labeled with ad-EGFP were injected intramyocardially into the peri-infarct area of rat models with acute myocardial infarction. Immunofluorescence staining exposed that CMGs expressed apelin together with myogenic-specific proteins such as α-actin, troponin T, GATA-4, and connexin-43 at 7 days after 5-AZ treatment or EGFP-BMSC injection. RT-PCR revealed that mRNA in CMGs started to express apelin and APJ from day 7 and progressively increased until day 28. Cardiac function, as measured by echocardiography in vivo, was significantly improved in parallel with the extent of apelin expression after BMSC transplantation. Our finding indicated that the expression of the apelin-APJ pathway during differentiation of BMSCs into CMGs may be an important mechanism in regulation of myocardial regeneration and functional recovery after BMSC transplantation.

Increased apelin following bone marrow mononuclear cell transplantation contributes to the improvement of cardiac function in patients with severe heart failure.

We previously reported that intracoronary implantation of bone marrow mononuclear cells (BMMC) into ischemic hearts improved cardiac function after myocardial infarction. However, the mechanisms have not been elucidated. The present study investigates whether apelin, a newly described inotropic peptide with important cardiovascular regulatory properties, contributes to the functional improvement in patients with severe heart failure after cell transplantation. Forty consecutive patients with severe heart failure secondary to myocardial infarction were assigned to the BMMC therapy group or the standard medication group according to each patient's decision on a signed consent document. In 20 patients intracoronary cell infusion was performed, and another 20 patients were matched to receive standard medication as therapeutic controls. An additional 20 healthy subjects were designated as normal controls. Clinical manifestations, echocardiograms, and biochemical assays were recorded. Plasma apelin and brain natriuretic protein (BNP) levels were determined by enzyme immunoassay. Baseline levels of plasma apelin were significantly lower in all heart failure patients compared to normal subjects. In patients who underwent cell transplantation, apelin increased significantly from 3 to 21 days after operation, followed by significant improvement in cardiac function. In parallel, BNP varied inversely with the increase of apelin. In patients receiving standard medical treatment, apelin remained at a lower level. Our findings indicated that increased apelin levels following cell therapy may act as a paracrine mediator produced from BMMCs and play an important role in the treatment of heart failure through autocrine and paracrine mechanisms.

[Transfection of bone marrow mesenchymal stem cells by adeno-associated virus 2/1 vector].

This study was aimed to investigate the transfection efficacy of recombinant adeno-associated virus 2/1 (rAAV2/1) on bone marrow mesenchymal stem cells (BMMSCs) at different multiplicities of infection (MOI) and time, and effect of transfection on growth of rat BMMSCs. The rat BMMSCs cultured in vitro were transfected by using rAAV2/1 with enhanced green fluorescent protein (rAAV2/1-EGFP) at MOI of 1 x 10(4), 1 x 10(5) and 1 x 10(6); the EGFP expression was observed by fluorescent microscopy at 3, 7 and 14 days. The viability, proliferation multiple, differentiation ability of daughter cells were detected for evaluating the effect of rAAV2/1 on survival, proliferation and differentiation of BMMSCs and the fluorescence index (FI) were determined by flow cytometry. The results indicated that after transfection with rAAV2/1 for 24 hours the green fluorescence in BMMSCs were observed, but also the fluorescence gradually was enhanced along with prolonging of time, and reached to steady level after 7 days; the viability, proliferation multiple, differentiation ability of BMMSCs transfected by rAAV2/1-EGFP at different MOI showed no significant changes at 3,7 and 14 days (p > 0.05), meanwhile at same MOI the proliferation multiple obviously increased in comparison between 7 day vs 3 day and 14 days vs 7 days (p < 0.01). The flow cytometric detection showed that the transfection efficacy of rAAV2/1-EGFP on BMMSCs and FI increased significantly as the multiplicity of infection and culture time increased (p < 0.05). It is concluded that rAAV2/1-EGFP is able to transfect into BMMSCs effectively, but the transfection efficiency and fluorescence index increase significantly along with increase of multiplicity of infection and culture time. rAAV2/1-EGFP do not affect viability, proliferation multiple and differentiation ability of BMMSCs. rAAV2/1 is a kind of active vector for gene transfer to reform BMMSCs.

[Autologous mononuclear bone marrow cell transplantation by intracoronary route for patients with ischemic heart disease: observation of 2-years follow-up].

OBJECTIVE: To investigate the long-term effect and safety of intracoronary autologous bone marrow mononuclear cell (BMMC) transplantation in patients with ischemic heart disease (IHD). METHODS: Seventy-six patients with IHD, 26 patients with acute myocardial infarction (AMI) and 26 patients with chronic ischemic heart failure (CIHF), underwent routine treatment plus intracoronary autologous BMMC transplantation, and 24 patients, including 10 patients with AMI and 14 patients with CIHF underwent routine treatment as controls. Autologous BMMC transplantation was performed via a balloon catheter placed into the infarct-related artery during balloon dilatation by high pressure infusion to occlude the artery, which was performed 6 - 8 times for 2 minutes each with 2-minute interval or via a balloon catheter without occluding the infarct-related artery. Follow-up was conducted for 2 years. RESULTS: The surgery was safety without major periprocedural complications. There were no other new arrhythmias found by Holter recorder during the 2-years follow-up. In the AMI patients receiving BNNC transplantation, the left ventricular ejection fraction (LVEF) 1 and 2 years later increased by 5.79% (P < 0.05), 3.79% (P > 0.05) respectively; but there was no change in left ventricular end diastolic volume (LVEDV) and left ventricular end systolic volume (LVESV). The LVEF 1 and 2 years later of the control group increased by 8.8% and 9.2% respectively (both P < 0.01) and the LVESV 1 and 2 years later decreased by 20.4% and 27.8% respectively (both P < 0.05), the myocardium defect area 2 years later was not significantly different from that 3 months later. The heart function of the control group became markedly worse. CONCLUSION: Autologous BMMC intracoronary transplantation is safe and effective, especially in patients with CIHF.

[The autologous bone marrow mononuclear cell transplantation by intracoronary route treat patients with severe heart failure after myocardial infarction].

OBJECTIVE: To investigate the chronic effects of intracoronary autologous bone marrow mononuclear cell (BM-MNCs) transplantation in patients with refractory heart failure (RIHF) after myocardial infarction. METHODS: Thirty patients with RIHF (LVEF < 40%) were enrolled in this nonrandomized study, autologous BM-MNCs (5.0 +/- 0.7) x 10(7) were transplanted with via infarct-related coronary artery in 16 patients and 14 patients received standard medical therapy served as control. Baseline and follow up evaluations included complete clinical evaluations, plasma BNP, ANP, ET-1 measurements, echocardiography, PET, and Holter monitoring. RESULTS: Baseline characteristics were similar between the 2 groups. There were no major periprocedural complications. One patient developed ventricular premature contractions during cell infusion for several seconds and recovered spontaneously. Compared to pre-transplantation, plasma BNP and ET-1 significantly decreased and plasma ANP significantly increased at 7 days post transplantation; 6 minutes walking distance increased from (72.1 +/- 31.5) to (201.6 +/- 23.3) m (P < 0.01), LVEF increased 9.9% (P < 0.001) and FDG-PET revealed vital myocardium area increased (10.3 +/- 3.4)% (P < 0.01) at 3 months after BM-MNCs transplantation. At 6 months follow up, the NYHA class improved from (3.4 +/- 0.1 to 2.4 +/- 0.2, P < 0.001) and no patient died and 1 patient rehospitalized due to lower extremities edema. In control group, LVEF decreased 7.2% compared to baseline (P < 0.001) and was significantly lower than transplantation group at 3 months (P < 0.001). At 6 months follow up, the NYHA class increased from (3.5 +/- 0.1 to 3.9 +/- 0.1, P < 0.05), 2 patients died and 10 patients rehospitalized due to aggravated heart failure. CONCLUSION: Present study demonstrates that intracoronary transplantation of autologous BM-MNCs is safe and effective for treating patients with RIHF after myocardial infarction.

Effect of intracoronary transplantation of autologous bone marrow-derived mononuclear cells on outcomes of patients with refractory chronic heart failure secondary to ischemic cardiomyopathy.

Recent studies have indicated that stem cell implantation increases cardiac function by repairing damaged myocardium. We investigated whether intracoronary transplantation of autologous bone marrow-derived mononuclear cells (BMMCs) confers beneficial effects in patients with refractory chronic heart failure. Twenty-eight patients received standard heart failure medication and BMMC transplantation (BMMC treatment) or standard medication only (controls). BMMCs were harvested from each patient. Clinical manifestations, biochemical assays, rhythm studies, echocardiograms, and positron emission tomograms were recorded. Fourteen patients with cell grafting had symptomatic relief of heart failure within 3 days. Left ventricular ejection fraction increased by 9.2% and 10.5% at 1 week and 3 months after the procedure, respectively, versus baseline (p < 0.01 for the 2 comparisons). Left ventricular end-systolic volume decreased by 30.7% after 3 months (p < 0.01). Brain natriuretic peptide levels at days 3 and 7 after cell infusion significantly decreased by 69.2% and 70.4%, respectively, whereas atrial natriuretic peptide levels increased by 30.1% at day 7. Positron emission tomographic analysis showed a significant increase in cell viability of 10.3% in the infarcted zone. No patient died in the BMMC-treated group at 6-month follow-up. In contrast, heart failure did not improve in any control patient. Left ventricular ejection fraction decreased by 7.2% after 3 months. Two control patients died from heart failure within 6 months. In conclusion, this is the first demonstration in humans that intracoronary BMMC transplantation is a feasible and safe therapeutic strategy to decrease symptoms, increase cardiac function, and possibly prolong life in patients with end-stage heart failure refractory to standard medical therapy.

[Transplantation of fetal cardiomyocyte regenerates infarcted myocardium in rats].

OBJECTIVE: To investigate the feasibility and efficiency of fetal cardiomyocyte transplantation into the rat model of myocardial infarction. METHODS: Cardiomyocytes were isolated from aborted human embryos aged 12 - 16 weeks and cultured for 5 days to confirm their viability. Rat model of extensive myocardial infarction (MI) was established in 18 male Wistar rats by ligating the descending anterior branch of left coronary artery and the 18 rats were randomly divided into 2 groups: transplantation group (n = 7, 2 x 10(6) fetal cardiomyocytes were transplanted into the myocardial scar) and culture medium injection group (n = 6, culture medium was injected into the myocardial scar) 5 days after extensive MI was caused. Another 6 rats undergoing sham operation were used as controls. Echocardiography was performed before and 60 +/- 3 days after the implantation to assess the left ventricular (LV) remodeling and cardiac function. Then the rats were killed and their heart were harvested to undergo HE staining, immunohistochemical examination with antibody against human alpha-actin smooth muscle (SMA) isoform, and light microscopy. RESULTS: Light microscopy revealed the presence of engrafted human fetal cardiomyocytes in the infarcted myocardium and the presence of nascent intercalated disks connecting the engrafted fetal cardiomyocytes and the host myocardium. The engrafted fetal cardiomyocytes were SMA positive. Serial echocardiography revealed that cell transplantation prevented scar thinning, LV further dilatation and dysfunction while the control animals developed scar thinning, significant LV dilatation accompanied by progressive deterioration in LV contractility. CONCLUSION: Fetal cardiomyocytes can be implanted and survive in the infarcted myocardial cells, thus preventing the scar thinning, and LV further dilatation and dysfunction.