Quadruple Valve Replacement with Mechanical Valves: An 11-Year Follow-up Study

<p><b>Background:</b> We performed the first quadruple valve replacement with mechanical valves, combined with the correction of complex congenital heart disease on November 17, 1999. We report here the 11-year follow-up study.</p><p><b>Methods:</b> A 47-year-old man with subacute rheumatic endocarditis, a ventricular septal defect, and an obstruction of the right ventricular outflow tract required replacement of the aortic, mitral, tricuspid, and pulmonary valves; repair of the ventricular septal defect; and relief of the obstruction of the right ventricular outflow tract. The surgery was done on November 17, 1999, after careful systemic preparation of the patient. Warfarin therapy with a target international normalized ratio (INR) range of 1.5 to 2.0 was used. Follow-up included monitoring the INR, recording the incidences of thromboembolic and bleeding events, electrocardiography, radiography, and echocardiography evaluations.</p><p><b>Results:</b> The patient's INR was maintained between 1.5 and 2.0. All 4 mechanical prosthetic heart valves worked well. He is in generally good health without any thromboembolic or bleeding complications.</p><p><b>Conclusions:</b> Long-term management is challenging for patients who have experienced quadruple valve replacement with mechanical valves; however, promising results could mean that replacement of all 4 heart valves in 1 operation is feasible in patients with quadruple valve disease, and an INR of 1.5 to 2.0 could be appropriate for Chinese patients with undergoing valve replacement with mechanical valves.</p>

Carboxy terminus of heat shock protein (HSP) 70-interacting protein (CHIP) inhibits HSP70 in the heart

Heat shock protein (HSP) 70 plays a critical role in protecting the heart from various stressor-induced cell injuries; the mechanism remains to be further understood. The present study aims to elucidate the effect of a probiotics-derived protein, LGG-derived protein p75 (LGP), in alleviating the ischemia/reperfusion (I/R)-induced heart injury. We treated rats with the I/R with or without preadministration with LGP. The levels of HSP70 and carboxy terminus of HSP70-interacting protein (CHIP) in the heart tissue were assessed by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The effect of CHIP on suppression of HSP70 and the effect of LGP on suppression of CHIP were investigated with an I/R rat model and a cell culture model. The results showed that I/R-induced infarction in the heart could be alleviated by pretreatment with LGP. HSP70 was detected in naïve rat heart tissue extracts. I/R treatment significantly suppressed the level of HSP70 and increased the levels of CHIP in the heart. A complex of CHIP/HSP70 was detected in heart tissue extracts. The addition of recombinant CHIP to culture inhibited HSP70 in heart cells. LGP was bound CHIP in heart cells and prevented the CHIP from binding HSP70. In summary, I/R can suppress HSP70 and increase CHIP in heart cells. CHIP can suppress HSP70 that can be prevented by pretreatment with LGP. The results imply that CHIP may be a potential target in the prevention of I/R-induced heart cell injury.

C1q/TNF-related proteins, a family of novel adipokines, induce vascular relaxation through the adiponectin receptor-1/AMPK/eNOS/nitric oxide signaling pathway

OBJECTIVE

Reduced plasma adiponectin (APN) in diabetic patients is associated with endothelial dysfunction. However, APN knockout animals manifest modest systemic dysfunction unless metabolically challenged. The protein family CTRPs (C1q/TNF-related proteins) has recently been identified as APN paralogs and some CTRP members share APN's metabolic regulatory function. However, the vasoactive properties of CTRPs remain completely unknown.

METHODS AND RESULTS

The vasoactivity of currently identified murine CTRP members was assessed in aortic vascular rings and underlying molecular mechanisms was elucidated in human umbilical vein endothelial cells. Of 8 CTRPs, CTRPs 3, 5, and 9 caused significant vasorelaxation. The vasoactive potency of CTRP9 exceeded that of APN (3-fold) and is endothelium-dependent and nitric oxide (NO)-mediated. Mechanistically, CTRP9 increased AMPK/Akt/eNOS phosphorylation and increased NO production. AMPK knockdown completely blocked CTRP9-induced Akt/eNOS phosphorylation and NO production. Akt knockdown had no significant effect on CTRP9-induced AMPK phosphorylation, but blocked eNOS phosphorylation and NO production. Adiponectin receptor 1, but not receptor 2, knockdown blocked CTRP9-induced AMPK/Akt/eNOS phosphorylation and NO production. Finally, preincubating vascular rings with an AMPK-inhibitor abolished CTRP9-induced vasorelaxative effects.

CONCLUSION

We have provided the first evidence that CTRP9 is a novel vasorelaxative adipocytokine that may exert vasculoprotective effects via the adiponectin receptor 1/AMPK/eNOS dependent/NO mediated signaling pathway.

Correction of tetralogy of fallot with combination of operative and interventional methods

A one-stage repair was planned for an 11-year-old boy with tetralogy of Fallot. After initial attempts to wean from cardiopulmonary bypass were unsuccessful, an atrial septal defect and a ventricular septal defect were created in order to achieve hemodynamic stability. The boy recovered from the operation but had large volume of chest drainage. Transthoracic echocardiography revealed left to right shunting at both atrial and ventricular levels. Interventional catheter-directed devices were used to repair the residual shunts successfully in the catheterization laboratory.

Microscopic origin of the giant ferroelectric polarization in tetragonal-like BiFeO(3)

We report direct experimental evidence for a room-temperature, ∼130  μC/cm(2) ferroelectric polarization from the tetragonal-like BiFeO(3) phase. The physical origin of this remarkable enhancement of ferroelectric polarization has been investigated by a combination of x-ray absorption spectroscopy, scanning transmission electron microscopy, and first principles calculations. A large strain-induced Fe-ion displacement relative to the oxygen octahedra, combined with the contribution of Bi 6s lone pair electrons, is the mechanism driving the large ferroelectric polarization in this tetragonal-like phase.

Increased expression of pigment epithelium-derived factor in aged mesenchymal stem cells impairs their therapeutic efficacy for attenuating myocardial infarction injury

AIMS

Mesenchymal stem cells (MSCs) can ameliorate myocardial infarction (MI) injury. However, older-donor MSCs seem less efficacious than those from younger donors, and the contributing underlying mechanisms remain unknown. Here, we determine how age-related expression of pigment epithelium-derived factor (PEDF) affects MSC therapeutic efficacy for MI.

METHODS AND RESULTS

Reverse transcriptase-polymerized chain reaction  and enzyme-linked immunosorbent assay analyses revealed dramatically increased PEDF expression in MSCs from old mice compared to young mice. Morphological and functional experiments demonstrated significantly impaired old MSC therapeutic efficacy compared with young MSCs in treatment of mice subjected to MI. Immunofluorescent staining demonstrated that administration of old MSCs compared with young MSCs resulted in an infarct region containing fewer endothelial cells, vascular smooth muscle cells, and macrophages, but more fibroblasts. Pigment epithelium-derived factor overexpression in young MSCs impaired the beneficial effects against MI injury, and induced cellular profile changes in the infarct region similar to administration of old MSCs. Knocking down PEDF expression in old MSCs improved MSC therapeutic efficacy, and induced a cellular profile similar to young MSCs administration. Studies in vitro showed that PEDF secreted by MSCs regulated the proliferation and migration of cardiac fibroblasts.

CONCLUSIONS

This is the first evidence that paracrine factor PEDF plays critical role in the regulatory effects of MSCs against MI injury. Furthermore, the impaired therapeutic ability of aged MSCs is predominantly caused by increased PEDF secretion. These findings indicate PEDF as a promising novel genetic modification target for improving aged MSC therapeutic efficacy.

The myocardial protective effects of adenosine pretreatment in children undergoing cardiac surgery: a randomized controlled clinical trial

OBJECTIVE

Adenosine pretreatment reduces injury caused by ischemia-reperfusion. To investigate the hypothesis that adenosine pretreatment would modulate injury induced by cardiopulmonary bypass (CPB) and myocardial ischemia/reperfusion, we conducted a randomized controlled trial on the effects of adenosine pretreatment in children undergoing surgery to repair congenital heart defects.

METHODS

Children undergoing surgery to repair congenital heart defects were randomized to adenosine pretreatment or control treatment. Adenosine pretreatment was performed by infusing a total of 2.45 mg kg⁻¹ of adenosine over 10 min. Serum troponin I was measured pre- and postoperatively. Multiple clinical parameters, including postoperative use of inotropic medicine and duration in the intensive care unit (ICU), were recorded.

RESULTS

A total of 82 patients were enrolled in the study. There were 42 control patients and 40 patients in the adenosine pretreatment group. The mean age and weight of the two groups were not significantly different, nor were cardiopulmonary bypass and cross-clamp times. There were no deaths and severe complications in both groups. The adenosine pretreatment protocol caused significant hypotension but had no significant effect on heart rate. One patient had severe tachycardia shortly after the adenosine pretreatment protocol was completed, and adenosine infusion was continued until CPB was started. Postoperative levels of serum troponin I were greater in the control patients than in the adenosine pretreatment group, indicating that the control group suffered greater myocardial injury. Control group patients required more postoperative inotropic agents than those in the adenosine pretreatment group at 0, 1, and 3 h, indicating that the adenosine pretreatment group had a better cardiac function. The adenosine pretreatment group also required significantly less time in the ICU than the control group (3.2 ± 1.2 days vs 3.9 ± 1.2 days, p = 0.013).

CONCLUSIONS

This study demonstrates that adenosine pretreatment is protective of the myocardium during open-heart surgery in pediatric patients.

Transthoracic occlusion for secundum atrial septal defects unsuitable for transcatheter occlusion approach

OBJECTIVE

Transcatheter occlusion of secundum atrial septal defects is a safe and effective alternative to traditional surgical closure; however, it is associated with serious occasional complications and inapplicable to more than 20% of atrial septal defects. In 2000, transthoracic occlusion was pioneered at Xijing Hospital as a novel method of atrial septal defect closure. The purpose of this study is to report the early and mid-term results of the transthoracic occlusion procedure and to evaluate its safety and efficacy.

METHODS

From April 2000 to April 2006, 268 patients with atrial septal defects were classified into 2 groups: group A (unsuitable for transcatheter occlusion, n = 126) and group B (n = 142). The transthoracic occlusion method used transesophageal echocardiographic-guided atrial septal defects occluder deployment via a right minithoracotomy without cardiopulmonary bypass or fluoroscopy.

RESULTS

Device implantation was successful in 265 patients (98.9%), including 9 elliptical devices in group A. The average size of circular occluders in group A was 38.2 ± 4.2 mm, which was larger than in group B (24.0 ± 4.5 mm) (P < .001). The average procedure time was 37.2 ± 9.2 minutes, the average intracardiac manipulation time was 5.8 ± 3.0 minutes, and the average inpatient stay was 3.2 ± 0.8 days. Twenty-five complications (9.3%) occurred in patients during the follow-up period. No large residual shunting, device embolization, or other severe complications resulted from transthoracic occlusion.

CONCLUSIONS

Transthoracic occlusion is a new safe and effective method for atrial septal defect treatment, even for patients with partial atrial septal defects unsuitable for transcatheter occlusion. This hybrid method broadens the indications of atrial septal defect treatment with device occlusion.

U50,488H postconditioning reduces apoptosis after myocardial ischemia and reperfusion

AIMS

Evidence has indicated U50,488H, a selective κ-opioid receptor (κ-OR) agonist, administered before ischemia attenuates apoptosis and infarction during ischemia and reperfusion (I/R). However, it remains unclear whether U50,488H postconditioning reduces apoptosis during I/R. This study was designed, therefore, to test the hypothesis that U50,488H administered at the onset of reperfusion inhibits cardiomyocyte apoptosis and to investigate the underlying mechanisms.

MAIN METHODS

Male Sprague-Dawley rats were subjected to myocardial ischemia and reperfusion(MI/R) and were randomized to receive either vehicle, U50,488H, U50,488H plus Nor-BNI, a selective κ-OR antagonist, U50,488H plus wortmannin, a specific inhibitor of phosphoinositide 3'-kinase (PI3K), or U50,488H plus L-NAME, a nitric oxide synthase inhibitor (NOS inhibitor), immediately prior to reperfusion. In vitro study was performed on cultured neonatal cardiomyocytes subjected to simulated ischemia/reperfusion.

KEY FINDINGS

Treatment with U50,488H resulted in increases in Akt and endothelial nitric oxide synthase (eNOS) phosphorylation with secondary NO production both in vivo and in vitro and these effect were completely blocked by wortmannin and specific Akt inhibitor(AI). L-NAME treatment had no effect on Akt and eNOS phosphorylation; but, significantly reduced NO production. Moreover, treatment with U50,488H markedly reduced myocardial apoptotic death. Treatment with wortmannin and specific Akt inhibitor abolished the anti-apoptotic effect of U50,488H. L-NAME also significantly attenuated the anti-apoptotic effect of U50,488H.

SIGNIFICANCE

These results demonstrate that U50,488H administered immediately prior to reperfusion increases Akt phosphorylation through a PI3-kinase-dependent mechanism and reduces postischemic myocardial apoptosis. Phosphorylation of eNOS with secondary NO production contribute significantly to the anti-apoptotic effect of U50,488H postconditioning.

Transcatheter device closure of perimembranous ventricular septal defects: mid-term outcomes

Aims

The aim of this study was to evaluate the safety and efficacy of transcatheter closure for perimembranous ventricular septal defect (pmVSD) and its long-term results. The most common congenital heart condition is pmVSD. Transcatheter closure of pmVSD is a recently described technique with limited results for mid- to long-term follow-up.

Methods and results

Between June 2002 and June 2008, 848 patients with pmVSD were enrolled in our study and treated percutaneously with pmVSD occluders. All patients were followed up until December 2008, an average of 37 months. According to colour Doppler transthoracic echocardiography before the intervention and ventriculography, the average end-diastolic pmVSD size was 5.1 and 5.4 mm, respectively. Placement of the device was successful in 832 patients (98.1%) and the median device size was 8.6 mm. During follow-up, 103 adverse events (12.4%) were reported. Most adverse events were categorized as minor and there were nine major adverse events (8.7%), including two complete atrioventricular block requiring pacemaker implantation. Kaplan–Meier estimates showed >85% freedom from major or minor adverse events during a maximal follow-up of 79 months.

Conclusions

In experienced hands, transcatheter pmVSD closure can be performed safely and successfully with low morbidity and mortality. Long-term prognostic results are favourable, and the transcatheter approach provides a less-invasive alternative that may become the first choice in selected pmVSD patients.

This trial is registered with ClinicalTrials.gov, number NCT00890799.

Totally thoracoscopic surgical resection of cardiac myxoma in 12 patients

Myxomas are the most common type of primary cardiac tumors. We report our use of totally thoracoscopic surgery in resecting cardiac myxomas in 12 cases with 10 in the left atria and 2 in the right atria. Totally thoracoscopic surgical resection of myxoma was successfully performed in all cases through three minimal incisions, with the largest incision less than 3 cm. The cardiopulmonary bypass time was 96 to 126 minutes, and the aortic cross-clamp time was 46 to 63 minutes. Postoperative ventilation assistance was 3 to 11 hours. We show that the method is safe and achieves complete tumor resection.

Surgical treatment of severe complications caused by transcatheter closure of ventricular septal defects

The objective was to report the surgical results following failed transcatheter intervention for closure of ventricular septal defects (VSDs). This study is a retrospective analysis of patients (n = 9) from Xijing Hospital (Xi'an, China) with failed transcatheter intervention for VSDs who subsequently underwent open heart surgery. Five patients experienced complications during transcatheter intervention, including third-degree atrioventricular block (III° AVB) (n = 2), aortic incompetence (n = 2), or tricuspid incompetence (n = 1). The devices were immediately removed in the catheterization laboratory followed by open heart surgery to repair VSDs. Four patients experienced complications after transcatheter intervention; one patient's device was displaced into the right ventricle, and 3 patients had III° AVB. These patients underwent surgery to retrieve the devices and to repair VSDs. All cardiac surgery was performed under general anesthesia and under cardiopulmonary bypass. Postoperatively, all patients recovered uneventfully with no deaths or complications. The patients with III° AVB after device implantation recovered sinus rhythm postoperatively, and tricuspid apparatus injuries were surgically repaired with valvuloplasty. Transcatheter interventional VSD closure is safe and effective, but only under the conditions of strict patient selection, proper technique, and device application. Once severe complications are observed and diagnosed, devices should be retrieved immediately, and open heart surgery should be performed to avoid further injury.

Connexin40 modulates pulmonary permeability through gap junction channel in acute lung injury after thoracic gunshot wounds

BACKGROUND

The permeability of pulmonary microvessel endothelial cells increases markedly after acute lung injury via paracellular gap. Connexin40 is a primary component of pulmonary microvessel endothelial cells gap junction channel and mediates intercellular communication. However, the relationship between connexin40 and the permeability of pulmonary microvessel endothelial cells is still unknown. Therefore, we determined whether connexin40 affected rabbits' pulmonary microvessel endothelial cells permeability after acute lung injury induced by gunshot trauma.

METHODS

We used an acute lung injury model in New Zealand rabbits following gunshot chest trauma and correlated connexin40 immunohistochemistry in gunshot lung tissue with Evans blue leak rate. Cultured pulmonary microvessel endothelial cells were divided into three groups, control (G control), injured serum (G serum), and blocker agent (G blocker). Gap junction channel function was assessed by scrape-loading and dye transfer techniques. Pulmonary microvessel endothelial cells permeability was measured by Evans blue-labeled albumin transfer.

RESULTS

Connexin40 expression decreased time dependently, whereas Evans blue leak rate increased. Connexin40 expression and Evans blue leak rate exhibited a strong inverse correlation (gamma = -0.934, p < 0.05). Injured serum decreased gap junction channel function, and the gap junction channel blocker aggravated this effect. Similarly, pulmonary microvessel endothelial cells permeability increased significantly in G serum and G blocker.

CONCLUSIONS

Connexin 40 expression in pulmonary microvasculature endothelial cells is downregulated after acute lung injury induced by gunshot trauma. This is associated with impaired gap junction channel function and increased pulmonary microvessel endothelial cells permeability.

[Enhancement of proliferation and differentiation of bone mesenchymal stem cells by basic fibrous growth factor controlled release nanoparticles]

This research was carried out to investigate the effect of basic fibrous growth factor (bFGF) controlled release hydrogel nanoparticles on the proliferation and differentiation of mesenchymal stem cells. The dex-GMA-bFGF-NPs were prepared by an improved emulsion polymerization method; their morphology, size and encapsulated ratio were assessed by routine procedure. Dynamic dialysis method was used to determine the release characteristics of dex-GMA-bFGF-NPs in vitro. The secondary culture MSCs were divided into four groups according the different ingredients being added into the DMEM culture medium: free bFGF group (A), blank dex-GMA nanoparticles group (B), dex-GMA-bFGF nanoparticles group (C), nothing group (D). The proliferation of cultured MSCs was measured by using cell counting method, MTT method and flow cytometry. ALP kit was used to evaluate the ALP activity of the MSCs to show the differentiation of the cells by adding the dex-GMA-bFGF-NPs to the DMEM culture medium (C group) or bFGF only (A group). B group and D group were taken as the controls. The results were analyzed by statistical analysis software (SPSS11.0). All results showed that the shape of dex-GMA-bFGF-NPs was spherical. The encapsulated ratio was 88% and more than 85% of the encapsulated bFGF could be released during 14 days. The in vitro cellular study showed the control release of bFGF from nanoparticles could promote the proliferation of MSCs. After 12 days, the cell number in groups A, B and C was (21.97 +/- 0.25) x 10(4) cells/ml, (12.43 +/- 0.13) x 10(4) cells/ml, (27.45 +/- 0.78) x 10(4) cells/ml and (12.03 +/- 0.43) x 10(4) cells/ml, with the difference being statistically significant among them (P < 0.05). The flow cytometry revealed that the G2/M+S percentage in group C was the highest at 4-8 days after plate culture(P < 0.05). During the first 3 days, the proliferation and differentiation of BMSCs between group A and group B were of no significance (P > 0.05), but were much faster than those of group C and D. After 7 days, dex-GMA-bFGF-NPs could enhance BMSCs proliferation and differentiation continually, but bFGF had no enhancement any more, the difference between group A and group B became more significant (P < 0.05). So we made the conclusions the bFGF loading dex-GMA hydrogel nanoparticles can release bFGF more than 21 days and can promote the proliferation and differentiation of the BMSCs through a long period of controlled release of bFGF. Dex-GMA-bFGF-NPs may be an ideal controlled release carrier for bioactive growth factors.

Gap junction channel modulates pulmonary vascular permeability through calcium in acute lung injury: an experimental study

BACKGROUND

Increased pulmonary vascular permeability is a hallmark of acute lung injury (ALI). Gap junction channels (GJCs) connect adjacent cells and facilitate ion exchange. It remained unclear whether GJCs modulate pulmonary permeability in ALI through intracellular calcium.

OBJECTIVES

This study aimed to verify if GJCs in pulmonary microvessel endothelial cells (PMVECs) modulate pulmonary vascular permeability in ALI via intracellular calcium.

METHODS

Firstly, an animal model of ALI was studied using connexin 40 (Cx40) immunohistochemistry in the lung with Evans' blue (EB) leakage. Then cultured PMVECs were divided into three groups: G(control), G(serum) and G(blocker). Serum was obtained from animals with ALI following gunshot injury (injured serum). Initially, G(blocker) was treated with the blocker of GJCs, and then G(serum) and G(blocker) were stimulated with the injured serum, respectively. GJCs, the permeability of cell monolayers and intracellular Ca(2+) were assessed.

RESULTS

Cx40 time-dependently decreased, whereas EB leakage increased. Cx40 and EB leakage exhibited a strong inverse correlation (rho = -0.934, p < 0.05). Injured serum decreased GJCs and expression of Cx40, whereas the blocker aggravated this effect. Similarly, when PMVEC monolayer was treated with injured serum, both permeability and intracellular Ca(2+) increased. These effects were also aggravated with the blocker.

CONCLUSIONS

Depression of GJCs of PMVECs increased pulmonary vascular permeability in ALI; this effect may be mediated by the overload of intracellular calcium.

Looking beyond the obvious: IgA nephropathy in a liver transplant recipient

Seventeen years after a liver transplant for biliary atresia, an adolescent presented with renal failure. The serum level of cyclosporine was sub-therapeutic; and, in spite of dosage adjustments, the patient’s status did not improve. Given the patient’s age, future renal transplant was a feasible consideration. However, this warranted investigation in the form of a renal biopsy in an attempt to confirm the underlying cause(s) of her renal failure. The renal biopsy revealed marked alteration in the renal anatomy due to IgA deposition, interstitial fibrosis, and hyaline arteriopathy.

Myocardial protective effect of urethane on isolated rat hearts in prolonged hypothermic preservation

BACKGROUND

One of the most important factors restricting heart transplantation is the limited myocardial ischemia time. This study investigated the effects of urethane on the hypothermic preservation of donor rat hearts.

MATERIALS AND METHODS

Hearts isolated from rats were divided into 2 groups (n = 8), a control group with histidine-tryptophan-ketoglutarate (HTK) solution alone and an experimental group with HTK solution plus 30 mM urethane. Hearts were mounted on a Langendorff apparatus to estimate the baseline cardiac function; the hearts were then arrested and stored in one of the 2 solutions for 6 hours and 18 hours at 4 degrees C. After preservation, the hearts were reperfused, and cardiac function was evaluated. Lactate dehydrogenase (LDH) release, adenosine triphosphate (ATP) content, cardiomyocyte apoptosis, and myocardial ultrastructure were examined.

RESULTS

Compared with the control group, the experimental group showed a significantly higher recovery of cardiac function for both 6 hours and 18 hours of preservation and demonstrated a lower rate of cardiomyocyte apoptosis (8.5% + or - 1.2% versus 12.2% + or - 1.8% for 6 hours; 14.1% + or - 2.1% versus 31.4% + or - 2.7% for 18 hours). ATP content was significantly higher in the experimental group than in the control group after 18 hours of preservation (229.4 + or - 29.7 microg/g versus 153.2 + or - 21.1 microg/g). The experimental group also showed lower levels of LDH release after 18 hours of preservation. Electron microscopy studies demonstrated better cardiomyocyte structure in the experimental group for both 6 hours and 18 hours of preservation.

CONCLUSIONS

Use of urethane improved cardiac functional recovery and led to significant protective effects on rat hearts placed in a hypothermic preservation solution for a prolonged period.