TNFR gene-modified mesenchymal stem cells attenuate inflammation and cardiac dysfunction following MI

OBJECTIVES: To investigate the protective effect of tumor necrosis factor receptor (TNFR) gene modified mesenchymal stem cells (MSCs) transplantation against inflammation and cardiac dysfunction following acute myocardial infarction (AMI). DESIGN: MSCs were extracted from the tibias and femurs of rats and transfected with recombinant adeno-associated viral (rAAV) expressing EGFP (enhanced green fluorescent protein) or p75 (human 75 kilodalton) TNFR at multiplicity of infection of 10(5) particles/cell. Rats with AMI induced by occlusion of the left coronary artery were randomized to MSCs-TNFR transplantation group, MSCs-EGFP transplantation group and MI control group. RESULTS: The effects of MSCs-TNFR transplantation on cardiac inflammation and left ventricular dysfunction were observed after 2 weeks of MI. We found that: 1) MSCs-TNFR transplantation attenuated protein production and gene expression of inflammatory cytokines TNF-, IL-1beta and IL-6; 2) MSCs-TNFR transplantation inhibited cardiomyocytes apoptosis and 3) MSCs-TNFR transplantation improved left ventricular function. CONCLUSIONS: The experimental data show that transplantation with rAAV-TNFR transfected MSCs improves left ventricular function following MI through anti-apoptotic and anti-inflammatory mechanisms.     

Optimal temporal delivery of bone marrow mesenchymal stem cells in rats with myocardial infarction.

OBJECTIVE: This study was designed to determine the optimal time point for bone marrow mesenchymal stem cell (MSC) transplantation after myocardial infarction (MI). METHODS: MSCs from donor rats were labeled with DAPI before transplantation. The animals underwent MI by ligation of left anterior descending coronary artery, and received intramyocardial injection of MSCs at 1h, 1 week and 2 weeks after MI, respectively. Sham-operated and MI control groups received equal volume phosphate buffered saline. Cardiac function, histological analysis and immunoblot for troponin T were performed 4 weeks after cell transplantation. RESULTS: MSC transplantation attenuated left ventricular chamber dilation, reduced infarct size, and improved cardiac function in rats after MI. The greatest benefit was achieved in rats that received cells 1 week after MI, engrafted MSC survival, angiogenesis and functional cardiomyocytes in the injured hearts were more abundant in these rats than that in other transplantation groups. CONCLUSIONS: The optimal functional benefit of MSC transplantation was observed in 1-week transplantation group. At this time point scar formation has not occurred and the inflammation is reduced, which should facilitate integration of transplanted cells and functional recovery.     

肝细胞生长因子及骨髓间充质干细胞联合移植治疗慢性缺血性心脏病的实验研究

目的研究经肝细胞生长因子(HGF)及骨髓间充质干细胞(MSCs)联合移植治疗慢性缺血性心脏病的疗效。方法采集香猪髂骨骨髓,用密度梯度法和贴壁分离法相结合的方法分离、培养MSCs,通过细胞表面标记(CD34、CD44、CD71、Ⅷ因子和desmin)成份鉴定;HGF基因的重组腺病毒(AdHGF)+MSCs共培养并检验HGF对MSCs生物学特征的影响。经左胸冠状动脉回旋支放置Ameroid环建立慢性心肌缺血香猪模型,将40只小型香猪采用随机对照分为5组(n=8),于缺血心肌处分别注射5×106/ml MSCs+4×109pfu 200μl AdHGF(MSCs+AdHGF组)、4×109pfu 200μl AdHGF(AdHGF组)、5×106/ml MSCs 200μl(MSCs组),4×109pfu 200μl AdNull(AdNull组)和生理盐水1 ml(对照组)。治疗4周后行心脏超声心动图,数字减影动脉造影(DSA),单光子发射计算机体层摄影(SPECT)心肌灌注检查及心肌凋亡细胞等检测。结果流式细胞仪检测MSCs表面标记CD44、CD71阳性,CD34、Ⅷ因子、desmin阴性;增殖细胞抗原(PCNA)蛋白表达显示HGF具有较强刺激MSCs增殖分化作用;彩色超声心动图检查提示:经治疗后MSCs+AdHGF组左心室舒张期末容积(LVEDV)、左心室射血分数(LVEF)、短轴缩短率(FS)明显改善,差异有统计学意义(P<0.05);DSA检测缺血区新生血管数MSCs+AdHGF组较AdHGF组、MSCs组明显增多,差异有统计学意义(P<0.05);SPECT显示MSCs+AdHGF组左室心肌增厚、灌注明显改善,运动增强,差异有统计学意义(P<0.05);心肌HE染色血管密度,MSCs+AdHGF组明显高于AdHGF组和MSCs组[(39.4±1.2)个/HPF vs.(36.5±1.4)个/HPF、(34.5±1.7)个/HPF,P<0.05];心肌TUNEL染色法检测,MSCs+AdHGF组、AdHGF组细胞凋亡率明显低于MSCs组(P<0.05)。结论 MSCs+AdHGF联合具有促进慢性缺血心肌新血管生成、抑制细胞凋亡、改善心功能等作用;MSCs+AdHGF联合治疗缺血性心脏病作用较单纯HGF或MSCs移植更明显。     

Late effects of renal transplantation on endothelial functions and cardiac morphology

Background

Endothelial dysfunction is common in patients undergoing hemodialysis (HD), and cardiovascular morbidity and mortality are higher in these patients. In this study, we evaluated the late posttransplantation effects of cyclosporine and tacrolimus on endothelial function, inflammation, and cardiac architecture.

Methods

The study included 12 patients undergoing hemodialysis (group 1); 22 renal transplant recipients, of which 13 were receiving cyclosporine therapy (group 2) and 9 were receiving tacrolimus therapy (group 3); and 12 healthy control individuals (group 4). Kidney recipients were included if the transplantation procedure had been performed at least 1 year before the study. Asymmetric dimethylarginine, C-reactive protein, carotid intima-media thickness, left ventricular posterior wall thickness, interventricular septal thickness, left ventricular muscle mass index, flow-mediated dilation, and nitroglycerine-induced dilation of the brachial artery were evaluated.

Results

Serum asymmetric dimethylarginine, C-reactive protein, carotid intima-media thickness, left ventricular posterior wall thickness, interventricular septal thickness, and left ventricular muscle mass index values were significantly higher in patients undergoing HD than in the other 3 groups (P < .05), whereas percent change in flow-mediated dilation and nitroglycerine-induced dilation of the brachial artery was significantly lower (P < .05).

Conclusion

Patients undergoing HD demonstrate endothelial dysfunction. In the late posttransplantation period, kidney recipients seem to have similar endothelial function and cardiac architecture as in the healthy population. This result may explain the reduction in cardiovascular morbidity and mortality after transplantation in patients undergoing HD. Tacrolimus and cyclosporine have similar effects on endothelial function.     

Accelerated renal fibrosis in cardiorenal syndrome is associated with long-term increase in urine neutrophil gelatinase-associated lipocalin levels

Background: Cardiac events are the main cause of death among patients with end-stage renal failure. Even a mild renal disease is currently considered a major risk factor for cardiovascular complications following myocardial infarction (MI). The aim of the present study was to detect histological, sera and urine characteristics of kidney injury in cardiorenal syndrome (CRS) compared to chronic kidney disease (CKD) with an intact cardiac function. Methods: We employed a rat model for CRS, in which an acute MI (AMI) was induced 4 weeks after establishment of subtotal nephrectomy. Four weeks later, left ventricular function was assessed by echocardiography and changes in renal performance were examined using histological and biochemical parameters. Results: Increased interstitial fibrosis as well as renal inflammation were observed in renal sections derived from CRS rats, compared to subtotal nephrectomy (CKD)-only animals. Moreover, we found that even though AMI on the background of CKD was not associated with a further decrease in creatinine clearance or a further increase in sera BUN levels compared to CKD only, a significant long-term elevation in urine neutrophil gelatinase-associated lipocalin (Ngal) levels was detectable post-MI induction. Conclusions: AMI in the CKD setting is associated with accelerated renal fibrosis and long-term elevated urine Ngal values, suggesting that cardiac dysfunction contributes to accelerated intrinsic kidney injury in CKD. The data indicate that elevated urine Ngal may potentially serve as an early non-invasive laboratory parameter for a left ventricular dysfunction-related renal injury.     

Expression of the tissue inhibitor of metalloproteinase-3 by transplanted VSMCs modifies heart structure and function after myocardial infarction

ObjectivesExtracellular matrix (ECM) remodelling is a critical aspect of cardiac remodelling following myocardial infarction. Tissue inhibitors of metalloproteinases (TIMPs) are physiological inhibitors of matrix metalloproteinases (MMPs) that degrade the ECM proteins. TIMP-3 is highly expressed in the heart and is markedly downregulated in patients with ischaemic cardiomyopathy. Cell-based gene therapy can enhance the effects of cell transplantation by temporally and spatially regulating the release of the gene product. The purpose of this study was to investigate the role of TIMP-3 gene-transfected vascular smooth muscle cells (VSMCs) in modifying heart structure and function in rats when transplanted 3 days after myocardial infarction (MI).MethodsAnesthetised rats were subjected to coronary artery ligation followed 3 days later by thoracotomy and transplantation of TIMP-3 gene-transfected VSMCs, untransfected VSMCs or medium injected directly into the ischaemic myocardium. We assessed left ventricular structure and function by echocardiography and morphometry, and measured the levels of myocardial matrix metalloproteinase-2 and -9 (MMP-2, MMP-9), TIMP-3 and tumour necrosis factor-α (TNF-α) at 4 weeks post-myocardial infarction.ResultsTransplantation of TIMP-3 gene-transfected VSMCs and untransfected VSMCs significantly decreased scar expansion and ventricular dilatation 25 days post-transplantation (4 weeks after MI). MMPs and TNF-α levels were reduced in the transplantation groups when compared to the group that was given an injection of medium only. Transplantation of TIMP-3 gene-transfected VSMCs was more effective in preventing progressive cardiac dysfunction, ventricular dilatation and in reducing MMP-2, MMP-9 and TNF-α levels when compared to the transplantation of untransfected VSMCs.ConclusionsTIMP-3 gene transfection was associated with attenuated left ventricular dilation and recovery of systolic function after MI compared with the control. TIMP-3 transfection enhanced the effects of transplanted VSMCs in rats by inhibiting matrix degradation and inflammatory cytokine expression, leading to improved myocardial remodelling.     

Multipotent Cells of Monocytic Origin Improve Damaged Heart Function

Recently, we generated cells with multipotent properties from blood monocytes that in vitro differentiate into various somatic cell types. This experimental study investigated whether these programmable cells of monocytic origin (PCMO) succeed to restore left ventricular function after myocardial infarction (MI).
PCMO were generated from monocytes by exposition to RPMI medium containing M-CSF and IL-3 for 6 days. MI was induced in female Lewis rats ligating the left coronary artery. PCMO of male Lewis donors were injected either intramyocardially (i.my.) or intravenously (i.v.) 24 h or 6 days post-infarction.
Hemodynamic assessment after 60 days demonstrated significant improvement of left ventricular function following i.my. transplantation of PCMO as well as early (24 h post-infarction) i.v. application while nonmodulated monocytes failed to restore heart function. The Y-chromosome-specific SRY gene of male donor PCMO was detected exclusively in infarcted hearts of animals, which demonstrated improved cardiac function. Subdivision of infarcted hearts by microdissection localized the SRY gene-containing department to the left ventricle adjacent to the infarcted area whereas the right ventricle remained negative. Successful generation of PCMO in access numbers allows their autologous use as a new additive treatment for early restoration of cardiac function after MI.     

Transplantation KCNMA1 modified bone marrow‐mesenchymal stem cell therapy for diabetes mellitus‐induced erectile dysfunction

This study assessed the effect of KCNMA1 transfected bone marrow‐mesenchymal stem cells (BM‐MSCs) on the improvement of erectile function in diabetic rats. Sixty male Sprague–Dawley rats were injected with streptozotocin (STZ) and screened with apomorphine (APO) to establish diabetes mellitus‐induced erectile dysfunction (DMED). DMED rats were randomly divided into four groups: rats in each group underwent intracavernous injection with either phosphate buffer solution (DMED+PBS), nontransfected MSCs (DMED+MSCs), empty vector transfected MSCs (DMED+null‐MSCs) or KCNMA1 transfected MSCs (DMED+KCNMA1‐MSCs). Before injection, high levels of KCNMA1 expression were confirmed in KCNMA1‐MSCs using RT‐PCR and Western blotting. The lentivirus transfected MSCs maintained their potential for multidirectional differentiation. Four weeks after injection, erectile function was ascertained by measuring intracavernous pressure (ICP). Penile tissues were collected for immunohistochemical analysis. The expression of KCNMA1 in the corpus cavernosum was increased, and the DMED+KCNMA1‐MSCs group displayed a significant improvement of erectile function. We concluded that KCNMA1 was able to enhance the positive effect of MSCs in the treatment of diabetes‐associated erectile dysfunction.     

Stromal Vascular Fraction Transplantation as an Alternative Therapy for Ischemic Heart Failure: Anti-inflammatory Role

Background  

The aims of this study were: (1) to show the feasibility of using adipose-derived stromal vascular fraction (SVF) as an alternative to bone marrow mono nuclear cell (BM-MNC) for cell transplantation into chronic ischemic myocardium; and (2) to explore underlying mechanisms with focus on anti-inflammation role of engrafted SVF and BM-MNC post chronic myocardial infarction (MI) against left ventricular (LV) remodelling and cardiac dysfunction.     

Human Mesenchymal Stromal Cells Improve Cardiac Perfusion in an Ovine Immunocompetent Animal Model

Background: Mesenchymal stromal cells (MSCs) hold considerable promise in the treatment of ischemic heart disease. Most preclinical studies of MSCs for acute myocardial infarction (AMI) have been performed either in syngeneic animal models or with human cells in xenogeneic immunodeficient animals. A preferable pre-clinical model, however, would involve human MSCs in an immunocompetent animal. Methods: AMI was generated in adult sheep by inducing ischemia reperfusion of the second diagonal branch. Sheep (n = 10) were randomized to receive an intravenous injection of human MSCs (1 × 10⁶ cells/kg) or phosphate buffered saline. Cardiac function and remodeling were evaluated with echocardiography. Perfusion scintigraphy was used to identify sustained myocardial ischemia. Interaction between human MSCs and ovine lymphocytes was assessed by a mixed lymphocyte response (MLR). Results: Sheep receiving human MSCs showed significant improvement in myocardial perfusion at 1 month compared with baseline measurements. There was no change in ventricular dimensions in either group after 1 month of AMI. No adverse events or symptoms were observed in the sheep receiving human MSCs. The MLR was negative. Conclusion: The immunocompetent ovine AMI model demonstrates the clinical safety and efficacy of human MSCs. The human cells do not appear to be immunogenic, further suggesting that immunocompetent sheep may serve as a suitable pre-clinical large animal model for testing human MSCs.     

基因修饰的骨髓间充质干细胞移植于慢性心肌梗死模型的实验研究

目的 研究血管内皮生长因子（VEGF）165基因修饰的骨髓间充质干细胞（MSCs）移植于慢性心肌梗死模型后的血管新生及对心功能的作用。方法 同源重组法构建含有VEGF。基因的重组腺病毒载体（rAd—VEGF165）;密度梯度离心法分离骨髓单个核细胞,贴壁法培养兔MSCs;rAd—VFGF165转染MSCs,并用4,6-联脒-2-苯基吲哚（DAPI）标记MSCs;结扎前降支法建立兔心肌梗死模型,存活6周的实验动物36只随机分为3组：移植rAd—VFGF165转染的MSCs组（Ⅰ组）12只、单纯移植MSCs组（Ⅱ组）12只和只注射无血清培养基的对照组（Ⅲ组）12只。移植术后4周,超声法检测心脏功能,并同术前比较;荧光显微镜下观察MSCs分布情况;免疫组化法检测梗死区微血管密度。结果 移植4周后Ⅰ 组的MSCs存活率大于其他2组;Ⅰ组的左室射血分数、E／A比值和梗死区微血管密度与其他2组比较差异有统计学意义（P〈0．05）。结论 VEGF165基因和MSCs联合策略是治疗心肌梗死的有效方法,所产生的协同治疗效果大于单纯的MSCs移植。     

Pre-operative echocardiographic abnormalities and adverse outcome following renal transplantation

Background: Premature cardiovascular disease is now the leading cause of death in renal transplant recipients. Although patients with progressive renal disease have many of the conventional risk factors for cardiovascular disease these do not have the same predictive power as they do in the general population. Echocardiographic abnormalities, notably left ventricular hypertrophy, have been shown to be associated with adverse outcome in patients on dialysis. Methods: The echocardiograms were studied from 141 patients who were examined on the eve of renal transplantation between 1988 and 1990 to try to identify factors predicting outcome. Thirty-four patients have since died, 22 of cardiovascular disease. Ninety-three of the survivors and 27 of the dead patients had echocardiographic traces suitable for analysis. Results: Left ventricular mass index was increased in those patients who died (median 167 vs 134 g/m²; P=0.03), as were end-systolic (4.3 vs 3.4 cm; P<0.01) and end-diastolic (5.8 vs 5.2 cm; P<0.01) diameters. Systolic function was also more severely impaired (fractional shortening, 27 vs 33%; P<0.01). Apart from age, only systolic function and end systolic diameter were independent predictors of outcome in multivariate analysis. Conclusions: This pattern of echocardiographic abnormality is similar to that reported in long-term dialysis populations, despite the adverse effects on survival. Moreover, despite potential benefits of transplantation on cardiac function, left ventricular hypertrophy, ventricular dilatation and systolic dysfunction were all associated with adverse outcome following transplantation. We conclude that echocardiography identifies markers for premature death following transplantation and provides targets for therapeutic intervention.     

Autologous stem cell transplantation in acute myocardial infarction: The ASTAMI randomized controlled trial. Intracoronary transplantation of autologous mononuclear bone marrow cells,study design and safety aspects

Objectives

Intracoronary transplantation of different cell populations has been used in acute myocardial infarction (AMI) with promising results. The primary objective of the Autologous Stem cell Transplantation in Acute Myocardial Infarction (ASTAMI) study is to test whether intracoronary transplantation of autologous mononuclear bone marrow cells (mBMC) improves left ventricular ejection fraction (LVEF) after anterior wall AMI.

Design

The ASTAMI study is a randomized, controlled, prospective study. One hundred patients with acute anterior wall ST-elevation myocardial infarction (STEMI) treated with acute percutaneous coronary intervention (PCI) are randomized in a 1:1 way to either intracoronary transplantation of autologous mBMC 5–8 d after PCI or to control. Left ventricular function, exercise capacity, biochemical status, functional class, quality of life and complications are validated at baseline and during a 12-month follow-up.

Results

By August 2004, out of 1004 patients with STEMI, 49 patients have been included in the study. Twenty-four patients have been randomized to intracoronary mBMC transplantation. Twenty patients had chest pain and 16 patients had ischemic ECG changes during the mBMC transplantation procedure. One patient had ventricular fibrillation 24?h after transplantation.

Conclusions

Intracoronary transplantation of autologous mBMC in the acute phase after AMI is feasible and seems safe in the short term.     

光氧化处理脱细胞牛心包构建组织工程心肌补片的实验研究

目的 探讨经染料介导光氧化处理的脱细胞牛心包构建组织工程心肌补片的可行性。方法 新鲜牛心包先脱细胞,再经光氧化法处理,消毒后种植雄性SD骨髓间充质干细胞(MSCs)。结扎雌性大鼠左冠状动脉前降支,制作心肌梗死模型,1周后将符合心肌梗死标准的大鼠随机分成3组,心肌梗死对照组(MI)、补片组(P)、种细胞补片组(P+C)分别进行干预。4周后,超声评价心功能;2周、4周取材行组织学和免疫组化检查。结果 脱细胞处理完全去除了牛心包组织中的细胞,光氧化处理使组织结构致密;种植的细胞在组织表面形成连续的细胞层。P+C组牛心包心肌补片降解程度、微血管密度在2周、4周时均较P组大。超声评价补片4周后大鼠心功能,P+C组左室射血分数(LVEF)、左室缩短分数(LVFS)均较MI组和P组大,与MI组的差异有统计学意义。结论 光氧化处理脱细胞牛心包构建的组织工程心肌补片可以延缓心功能恶化,该处理方法具有良好的应用潜力。     

Use of the peak troponin value to differentiate myocardial infarction from reversible neurogenic left ventricular dysfunction associated with aneurysmal subarachnoid hemorrhage

OBJECT: Differentiating myocardial infarction (MI) from reversible neurogenic left ventricular dysfunction (stunned myocardium [SM]) associated with aneurysmal subarachnoid hemorrhage (SAH) is critical for early surgical intervention. The authors hypothesized that the cardiac troponin (cTn) trend and/or echocardiogram could be used to differentiate between the two entities. METHODS: A retrospective study was conducted for the period between 1995 and 2000. All patients included in the study met the following criteria: 1) no history of cardiac problems; 2) new onset of abnormal cardiac function (ejection fraction [EF] < 40% on echocardiograms); 3) serial cardiac markers (cTn and creatine kinase MB isoform [CK-MB]); 4) surgical intervention for their aneurysm; and 5) cardiac output monitoring either by repeated echocardiograms or invasive hemodynamic monitoring during the first 4 days post-SAH when the patients were euvolemic. Of the 350 patients with SAH, 10 (2.9%) had severe cardiac dysfunction. Of those 10, six were women and four were men. The patients' mean age was 53.5 years (range 29-75 years) and their SAH was classified as Hunt and Hess Grade III or IV. Aneurysm distribution was as follows: basilar artery tip (four); anterior communicating artery (two); middle cerebral artery (one); posterior communicating artery (two); and posterior inferior cerebellar artery (one). The mean EFonset was 33%. The changes on echocardiograms in these patients did not match the findings on electrocardiograms (EKGs). Within 4.5 days, dramatic improvement was seen in cardiac output (from 4.93 +/- 1.16 L/minute to 7.74 +/- 0.88 L/minute). Compared with historical controls in whom there were similar levels of left ventricular dysfunction after MI, there was no difference in peak CK-MB. A 10-fold difference, however, was noted in cTn values (0.22 +/- 0.25 ng/ml; control 2.8 ng/ml; p < 0.001). CONCLUSIONS: The authors determined the following: 1) that the CK-MB trend does not allow differentiation between SM and MI; 2) that echocardiograms revealing significant inconsistencies with EKGs are indicative of SM; and 3) that cTn values less than 2.8 ng/ml in patients with EFs less than 40% are consistent with SM.     

Soluble factors from multipotent mesenchymal stromal cells have antinecrotic effect on cardiomyocytes in vitro and improve cardiac function in infarcted rat hearts

The mechanisms underlying the functional improvement after injection of multipotent mesenchymal stromal cells (MSCs) in infarcted hearts remain incompletely understood. The aim of this study was to investigate if soluble factors secreted by MSCs promote cardioprotection. For this purpose, conditioned medium (CM) was obtained after three passages from MSC cultures submitted to 72 h of conditioning in serum-free DMEM under normoxia (NCM) or hypoxia (HCM) conditions. CM was concentrated 25-fold before use (NCM-25X, concentrated normoxia conditioned medium; HCM-25X, concentrated hypoxia conditioned medium). The in vitro cardioprotection was evaluated in neonatal ventricular cardiomyocytes by quantifying apoptosis after 24 h of serum deprivation associated with hypoxia (1% O(2)) in the absence or presence of NCM and HCM (nonconcentrated and 25-fold concentrated). The in vivo cardioprotection of HCM was tested in a model of myocardial infarction (MI) induced in Wistar male rats by permanent left coronary occlusion. Intramyocardial injection of HCM-25X (n = 14) or nonconditioned DMEM (n = 16) was performed 3 h after coronary occlusion and cardiac function was evaluated 19-21 days after medium injection. Cardiac function was evaluated by electro- and echocardiogram, left ventricular catheterization, and treadmill test. The in vitro results showed that HCM was able to decrease cardiomyocyte necrosis. The in vivo results showed that HCM-25X administered 3 h after AMI was able to promote a significant reduction (35%) in left ventricular end-diastolic pressure and improvement of cardiac contractility (15%) and relaxation (12%). These results suggest that soluble factors released in vitro by MSCs are able to promote cardioprotection in vitro and improve cardiac function in vivo.     

Intravenous transplantation of mesenchymal stem cells improves cardiac performance after acute myocardial ischemia in female rats

Mesenchymal stem cells (MSCs) are potential sources of cells for tissue repairing. However, little information is available regarding the therapeutic potency of intravenously transplanted MSCs for myocardial ischemia (MI). In the present study, MSCs were isolated from bone marrow of male rats and expanded in vitro. Three hours after ligation of left anterior descending artery, the transplanted group received an infusion of MSCs through the tail vein. At the same time, a coronary-ligated control group was injected with culture medium. Homing of MSCs to the heart was assessed by expression of the Y chromosome sry gene using fluorescent in situ hybridization (FISH). At 1 week or 8 weeks after transplantation, sry positive cells were present in cardiac tissue in the transplanted group, but not in the hearts of control group. Cardiomyocytes, smooth muscle cells, and endothelial cells that bore sry gene were identified in transplanted group at 8 weeks after transplantation. Ultrastructural observation revealed that a large number of capillary and some immature myocytes were found to survive in the ischemia region. MSCs transplantation also decreased LVEDP pressure and -dP/dt, but increased LVSP and +dP/dt. The cardiac infarct size was significantly smaller in transplanted group than in control group. Our data suggest that intravenously transplanted MSCs improve cardiac performance and promote the regeneration of blood vessels and cardiomyocytes.     

Therapeutic implications of mesenchymal stem cells transfected with hepatocyte growth factor transplanted in rat kidney with unilateral ureteral obstruction

Purpose

The purpose of the study was to establish whether bone marrow mesenchymal stem cells (MSCs) transfected with hepatocyte growth factor (HGF) can migrate and localize in the rat's kidney with unilateral ureteral obstruction (UUO) and contribute to repair of renal fibrosis.

Methods

We separated and cultured bone marrow-derived MSCs of male rats in vitro and transfected them with adenovirus-mediated HGF (Ad-HGF). The expression of HGF was measured with enzyme-linked immunosorbent assay. Sixty female rats were sham operated (n = 24) or subjected to left UUO: Ad-HGF-transfected MSCs, uninfected MSCs, or saline was injected into the rat's tail vein. Kidney tissue was collected at the end of the seventh or 14th day after operation. The distribution of Y chromosome in the kidney after Ad-HGF-transfected MSCs transplantation was determined by an in situ hybridization method. As the hallmark of myofibroblasts, α-smooth muscle actin (expression of which significantly increases in the presence of renal fibrosis) was detected by immunohistochemistry in all UUO rats' left kidney tissue.

Results

Y chromosome-positive cells were found only in the obstructed kidney of the transplantation group. The positive cells were mainly distributed in the tubular cells. The average intensity of immunolabeling for α-smooth muscle actin in the transplanted group significantly decreased compared with sham-transplanted group (P < .05), and the expression in the rats injected with uninfected MSCs was higher than that in the rats with MSCs transfected with HGF (P < .05).

Conclusions

Mesenchymal stem cells transfected with HGF can migrate to the rat kidney with UUO and are mainly distributed in the region of renal tubular epithelial cells. The data indicate that MSCs transfected with HGF contribute to a reduction of renal fibrosis after ureteral obstruction and suggest that this may be exploited therapeutically.     

Effects of pre-existing left ventricular hypertrophy on ventricular dysfunction and remodeling following myocardial infarction in rats.

BACKGROUND: Myocardial hypertrophy is a characteristic component of left ventricular (LV) remodeling that may, at least initially, have a beneficial effect on LV function following myocardial infarction (MI). In the present study, we examine the effects of pre-existing left ventricular hypertrophy (LVH) on LV function and chamber enlargement following MI in inbred Lewis rats. METHODS: The one-kidney, one-clip model (1K1C) of hypertension was used to produce LVH. Four weeks after 1K1C, rats were randomized to left anterior descending coronary artery ligation (LVH + MI group, n = 8) or sham ligation (LVH group, n = 11). Another group of rats underwent sham 1K1C. Four weeks later, they were randomized to coronary ligation (MI group, n = 12) or sham ligation (Sham group, n = 12). LV end-diastolic pressure (EDP, mm Hg), end-diastolic volume (EDV, ml), end-systolic volume (ESV, ml) and ejection fraction (EF) (determined by angiography) were measured in all groups 2 months after MI. RESULTS: LV EDP was 20 +/- 2 mm Hg in the LVH + MI group compared with 9 +/- 1 mm Hg in the MI group (p < 0.05). LV EDV and ESV were significantly greater with LVH + MI than with MI alone (EDV 0.90 +/- 0.03 vs 0.75 +/- 0.02 ml; ESV 0.68 +/- 0.02 vs 0.50 +/- 0.03 ml; p < 0.05). Pre-existing LVH resulted in a greater reduction in EF following MI (25 +/- 2% for LVH + MI vs 34 +/- 2% for MI alone; p < 0.05). CONCLUSIONS: Pre-existing LVH is an important determinant of progressive LV dysfunction and remodeling following MI in Lewis inbred rats.