Adipose-derived stem cells attenuate pulmonary arterial hypertension and ameliorate pulmonary arterial remodeling in monocrotaline-induced pulmonary hypertensive rats

Tumor Necrosis Factor-α-Induced Protein-8-like 2 Transfected Adipose-Derived Stem Cells Regulated the Dysfunction of Monocrotaline Pyrrole-Induced Pulmonary Arterial Smooth Muscle Cells and Pulmonary Arterial Endothelial Cells

ABSTRACT

Pulmonary arterial hypertension (PAH) is characterized by pulmonary arterial endothelial cell (PAEC) dysfunction and pulmonary arterial smooth muscle cell (PASMC) activation. For decades, the therapies for PAH based on stem cells have been shown to be effective. Meanwhile, tumor necrosis factor-α-induced protein-8-like 2 (TIPE2) promote the viability of human amniotic mesenchymal stem cells. Therefore, we aimed to explore the role of TIPE2 in adipose-derived stem cells (ADSCs) and the function of TIPE2-transfected ADSCs in the regulation of PAH. We first explored the role and underlying molecular mechanism of TIPE2 in viability and migration of ADSCs. Moreover, the ADSCs transfected with TIPE2 were cocultured with monocrotaline pyrrole (MCTP)-stimulated PASMCs or PAECs. The effects and mechanisms of TIPE2-transfected ADSCs on MCTP-induced PASMCs and PAECs were further investigated. The results showed that TIPE2 overexpression promoted viability and migration of ADSCs by activating the TLR4-ERK1/2 pathway. In addition, TIPE2-transfected ADSCs inhibited the abnormal proliferation and the impaired apoptosis of PASMCs via NF-κB signaling and promoted the conversion of PASMCs from synthetic to contractile. Meanwhile, TIPE2-transfected ADSCs reduced the apoptosis, endothelial-to-mesenchymal transition, and migration of PAECs via PI3K/AKT signaling after MCTP treatment. MCTP-induced oxidative stress and inflammation of PAECs were significantly decreased by TIPE2-transfected ADSCs. In rat model, TIPE2-ADSCs administration further decreased the monocrotaline-induced increase in the right ventricular systolic pressure and ratio of right ventricle weight/left ventricle and septa weight (L + S) and right ventricle weight/body weight compared with the ADSCs group. In conclusion, TIPE2-transfected ADSCs dramatically attenuated the PAH via inhibiting the dysfunction of PASMCs and PAECs.

RNA sequencing analysis of monocrotaline-induced PAH reveals dysregulated chemokine and neuroactive ligand receptor pathways

Pulmonary arterial hypertension (PAH) is a serious disease characterized by elevated pulmonary artery pressure, inflammatory cell infiltration and pulmonary vascular remodeling. However, little is known about the pathogenic mechanisms underlying the disease onset and progression. RNA sequencing (RNA-seq) was used to identify the transcriptional profiling in control and rats injected with monocrotaline (MCT) for 1, 2, 3 and 4 weeks. A total of 23200 transcripts and 280, 1342, 908 and 3155 differentially expressed genes (DEGs) were identified at the end of week 1, 2, 3 and 4, of which Svop was the common top 10 DEGs over the course of PAH progression. Functional enrichment analysis of DEGs showed inflammatory/immune response occurred in the early stage of PAH development. KEGG pathway enrichment analysis of DEGs showed that cytokine-cytokine receptor interaction and neuroactive ligand-receptor interaction were in the initiation and progression of PAH. Further analysis revealed impaired expression of cholinergic receptors, adrenergic receptors including alpha1, beta1 and beta2 receptor, and dysregulated expression of γ-aminobutyric acid receptors. In summary, the dysregulated inflammation/immunity and neuroactive ligand receptor signaling pathways may be involved in the onset and progression of PAH.

Therapeutic efficacy of mesenchymal stromal cells and secretome in pulmonary arterial hypertension: A systematic review and meta-analysis

Mesenchymal stromal cells (MSCs) and secretome are promising therapies for pulmonary arterial hypertension (PAH). This meta-analysis aimed to provide a precise estimate and compare the therapeutic efficacy of MSC and secretome in PAH. We searched six databases (CINAHL, Cochrane, Ovid Medline, PubMed, Science Direct and Scopus) until December 2018 using search terms related to MSCs, secretome and PAH. Twenty-three studies were included for the meta-analysis. The effect size of pulmonary hemodynamics and right ventricular hypertrophy markers was estimated using random effects model. MSCs and secretome significantly improved pulmonary hemodynamics and right ventricular hypertrophy compared to control. Comparison between MSCs and secretome indicate no significant difference in reducing right ventricular systolic pressure (RVSP) and medial wall thickening (MWT). However, treatment of PAH with secretome significantly improved mean pulmonary arterial pressure (mPAP) (p = 0.018) and right ventricular/left ventricular + septum (RV/LV+S) (p = 0.017) better than MSCs. Meta-regression shows that cell type (p = 0.034) is a predictor of MSCs to reduce RVSP in PAH. Similarly, the effect of secretome on MWT was significantly (p = 0.011) better at 4 weeks compared to 2 weeks of intervention. The overall risk of bias ranges from low to moderate; however, some of the essential elements required in reports of animal trials were not reported. There was evidence of publication bias for RV/LV+S and MWT, but not RVSP. This meta-analysis provides evidence of the therapeutic benefits of MSCs and secretome in PAH and the effect of secretome was similar or superior to MSCs.

Regenerative cell therapy for pulmonary arterial hypertension in animal models: a systematic review

Background

Pulmonary arterial hypertension (PAH) is a rare disease characterized by widespread loss of the pulmonary microcirculation and elevated pulmonary arterial pressures leading to pathological right ventricular remodeling and ultimately right heart failure. Regenerative cell therapies could potentially restore the effective lung microcirculation and provide a curative therapy for PAH. The objective of this systematic review was to compare the efficacy of regenerative cell therapies in preclinical models of PAH.

Methods

A systematic search strategy was developed and executed. We included preclinical animal studies using regenerative cell therapy in experimental models of PAH. Primary outcomes were right ventricular systolic pressure (RVSP) and mean pulmonary arterial pressure (mPAP). The secondary outcome was right ventricle/left ventricle + septum weight ratio (RV/LV+S). Pooled effect sizes were undertaken using random effects inverse variance models. Risk of bias and publication bias were assessed.

Results

The systematic search yielded 1285 studies, of which 44 met eligibility criteria. Treatment with regenerative cell therapy was associated with decreased RVSP (SMD − 2.10; 95% CI − 2.59 to − 1.60), mPAP (SMD − 2.16; 95% CI − 2.97 to − 1.35), and RV/LV+S (SMD − 1.31, 95% CI − 1.64 to − 0.97). Subgroup analysis demonstrated that cell modification resulted in greater reduction in RVSP. The effects on RVSP and mPAP remained statistically significant even after adjustment for publication bias. The majority of studies had an unclear risk of bias.

Conclusions

Preclinical studies of regenerative cell therapy demonstrated efficacy in animal models of PAH; however, future studies should consider incorporating design elements to reduce the risk of bias.

Systematic review registration

Suen CM, Zhai A, Lalu MM, Welsh C, Levac BM, Fergusson D, McIntyre L and Stewart DJ. Efficacy and safety of regenerative cell therapy for pulmonary arterial hypertension in animal models: a preclinical systematic review protocol. Syst Rev. 2016;5:89.

Trial registration

CAMARADES-NC3Rs Preclinical Systematic Review & Meta-analysis Facility (SyRF). http://syrf.org.uk/protocols/. Syst Rev 5:89, 2016

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1172-6) contains supplementary material, which is available to authorized users.

Efficacy of stem cell therapy for pulmonary arterial hypertension: a systematic review and meta-analysis of preclinical studies

Background

Despite significant progress in drug treatment, the prognosis of patients with advanced pulmonary arterial hypertension (PAH) remains extremely poor. Many preclinical studies have reported the efficacy of stem cell (SC) therapy for PAH; however, this approach remains controversial. The aim of this systematic review and meta-analysis is to assess the potential efficacy of SC therapy for PAH.

Methods

The Medline, EMBASE, Cochrane Library, and Web of Science databases were searched from inception to August 12, 2018. Preclinical studies that evaluated the use of SC therapy for PAH were included. The primary outcome was pulmonary haemodynamics, as assessed by measurement of the right ventricular systolic pressure (RVSP), mean pulmonary arterial pressure (mPAP), and/or mean right ventricle pressure (mRVP). The secondary outcomes included the weight ratio of the right ventricle to the left ventricle plus septum (RV/LV+S), the right ventricle to body weight ratio (RV/BW), the percentage of pulmonary arteriole area index (WA), and/or the percentage of medial wall thickness of the pulmonary arteriole (WT). The quality of outcomes was evaluated using the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) bias risk tool. The inverse-variance method with random-effects modelling was used to calculate pooled weighted mean differences (WMDs) and 95% CIs. Statistical analysis was performed with STATA 14.0.

Results

Twenty-eight eligible articles (722 animals) were included. SC therapy reduced the pooled WMDs (95% CIs) of RVSP, mPAP, mRVP, RV/LV+S, RV/BW, WA, and WT for animals with PAH, with values of − 14.12 (− 14.63, − 13.61), − 11.86 (− 12.35, − 11.36), − 17.33 (− 18.10, − 16.56), − 0.10 (− 0.10, − 0.09), 0.23 (0.21, 0.24), − 13.66 (− 15.71, − 11.62), and − 7.96 (− 7.99, − 7.93), respectively.

Conclusions

SC therapy is effective for PAH in preclinical studies. These results may help to standardise preclinical animal studies and provide a theoretical basis for clinical trial design in the future.

Systematic review registration

PROSPERO (http://www.crd.york.ac.uk/PROSPERO).

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1162-8) contains supplementary material, which is available to authorized users.

Development of a Rat Model of Sick Sinus Syndrome Using Pinpoint Press Permeation

Objective

Sick sinus syndrome (SSS) is one of the most common causes of cardiac impairment necessitating pacemaker implantation. However, studies of SSS pathogenesis are neither comprehensive nor conclusive due to limited success in achieving a stable rat SSS model. Here, we modified pinpoint press permeation to establish a stable rat SSS model.

Methods

We randomly assigned 138 male Sprague-Dawley rats into three groups: normal control (n = 8), sham (n = 10), and SSS (n = 120). Postoperatively, the SSS group was further divided into SSSA (n = 40), SSSB (n = 40), and SSSC (n = 40), based on reduction in heart rates by 20–30%, 31–40%, and 41–50%, respectively. We also assessed histomorphological characteristics and hyperpolarization-activated cyclic nucleotide-gated cation channel 4 (HCN4) expression in the sinoatrial node (SAN) at 1, 2, 3, and 4 weeks after surgery.

Results

Mortality was statistically higher in SSSC compared to SSSA and SSSB (7.5% versus 90.0% and 87.5%; P < 0.05). Heart rate in SSSA was gradually restored to preoperative levels by week 4 after surgery. In contrast, heart rate in SSSB was stable at 2–3 weeks after surgery. However, we observed that the tissues and cells in SAN were severely injured and also found a time-dependent increase in collagen content and atrium myocardium in SSSB. HCN4 expression was significantly reduced at all 4 time points in SSSB, with statistically significant differences among the groups (P < 0.01).

Conclusion

We successfully developed a rat SSS model that was sustainable for up to 4 weeks.

Pulmonary arterial hypertension induced by a novel method: Twice-intraperitoneal injection of monocrotaline

Pulmonary arterial hypertension (PAH) in humans manifests as a chronic process. However, PAH induced by high-dose monocrotaline (MCT) in animals occurs as a subacute process. To establish a chronic PAH model, rats were randomly divided into three groups, control (ctrl), single injection (SI), and twice injection (TI) groups. Rats in the SI group received a single intraperitoneal injection of 40 mg/kg MCT on day 0. Rats in the TI group received twice injections of 20 mg/kg MCT on days 0 and 7. Survival percentage, characteristic changes of pulmonary arterial variables, and right ventricular features were evaluated. Thirty-five days after the first MCT injection, survival percentage in TI group was higher than that in the SI group. The mean pulmonary arterial pressure (mPAP), right ventricular hypertrophy index (RVHI), pulmonary vascular remodeling, serum tumor necrosis factor α (TNFα), and interleukin-6 (IL-6) were higher either in SI or in TI 28 and 35 days after the first MCT injection. The rats in the SI and TI groups exhibited higher right ventricle end diastolic diameter (RVEDD) and lower adjusted pulmonary artery acceleration time (PAAT/HR), tricuspid annular plane systolic excursion (TAPSE), cardiac output (CO) and right ventricle fractional shortening (RVFS) when compared with controls. However, mPAP, RVHI, TAPSE, PAAT/HR, CO, TNFα, and IL-6 were lower and RVEDD were higher in the TI group than in the SI group. Pulmonary macrophage infiltration and right ventricle (RV) fibrosis were lower in TI than SI groups. The cardiomyocyte cross-sectional area and the beta myosin heavy chain (MYH7) mRNA level of RV were lower in TI than SI, whereas alpha myosin heavy chain (MYH6) was increased. These results show that two intraperitoneal injections of 20 mg/kg MCT with seven days interval could induce a model similar to chronic PAH with increased survival percentage in rats. Impact statement We demonstrated previously that a single intraperitoneal injection of 40 mg/kg MCT produced a subacute, not chronic, PAH model in rats, and the short survival periods of these rats did not represent adequately the chronic PAH seen in humans. To overcome this limitation, in this study, the single dose of 40 mg/kg MCT was divided into twice injections of 20 mg/kg with an interval of seven days. This modified administration of MCT produced an animal model much more similar to chronic PAH with prolonged survival and characteristic changes of structures and function in pulmonary arteries and right ventricles.

TRPM7 regulates angiotensin II-induced sinoatrial node fibrosis in sick sinus syndrome rats by mediating Smad signaling

Sinoatrial node fibrosis is involved in the pathogenesis of sinus sick syndrome (SSS). Transient receptor potential (TRP) subfamily M member 7 (TRPM7) is implicated in cardiac fibrosis. However, the mechanisms underlying the regulation of sinoatrial node (SAN) fibrosis in SSS by TRPM7 remain unknown. The aim of this study was to investigate the role of angiotensin II (Ang II)/TRPM7/Smad pathway in the SAN fibrosis in rats with SSS. The rat SSS model was established with sodium hydroxide pinpoint pressing permeation. Forty-eight rats were randomly divided into six groups: normal control (ctrl), sham operation (sham), postoperative 1-, 2-, 3-, and 4-week SSS, respectively. The tissue explant culture method was used to culture cardiac fibroblasts (CFs) from rat SAN tissues. TRPM7 siRNA or encoding plasmids were used to knock down or overexpress TRPM7. Collagen (Col) distribution in SAN and atria was assessed using PASM–Masson staining. Ang II, Col I, and Col III levels in serum and tissues or in CFs were determined by ELISA. TRPM7, smad2 and p-smad2 levels were evaluated by real-time PCR, and/or western blot and immunohistochemistry. SAN and atria in rats of the SSS groups had more fibers and higher levels of Ang II, Col I and III than the sham rats. Similar findings were obtained for TRPM7 and pSmad2 expression. In vitro, Ang II promoted CFs collagen synthesis in a dose-dependent manner, and potentiated TRPM7 and p-Smad2 expression. TRPM7 depletion inhibited Ang II-induced p-Smad2 expression and collagen synthesis in CFs, whereas increased TRPM7 expression did the opposite. SAN fibrosis is regulated by the Ang II/TRPM7/Smad pathway in SSS, indicating that TRPM7 is a potential target for SAN fibrosis therapy in SSS.

Stem cell therapy targeting the right ventricle in pulmonary arterial hypertension: is it a potential avenue of therapy?

Pulmonary arterial hypertension (PAH) is an incurable disease characterized by an increase in pulmonary arterial pressure due to pathological changes to the pulmonary vascular bed. As a result, the right ventricle (RV) is subject to an increased afterload and undergoes multiple changes, including a decrease in capillary density. All of these dysfunctions lead to RV failure. A number of studies have shown that RV function is one of the main prognostic factors for PAH patients. Many stem cell therapies targeting the left ventricle are currently undergoing development. The promising results observed in animal models have led to clinical trials that have shown an improvement of cardiac function. In contrast to left heart disease, stem cell therapy applied to the RV has remained poorly studied, even though it too may provide a therapeutic benefit. In this review, we discuss stem cell therapy as a treatment for RV failure in PAH. We provide an overview of the results of preclinical and clinical studies for RV cell therapies. Although a large number of studies have targeted the pulmonary circulation rather than the RV directly, there are nonetheless encouraging results in the literature that indicate that cell therapies may have a direct beneficial effect on RV function. This cell therapy strategy may therefore hold great promise and warrants further studies in PAH patients.

Combination treatment of adipose-derived stem cells and adiponectin attenuates pulmonary arterial hypertension in rats by inhibiting pulmonary arterial smooth muscle cell proliferation and regulating the AMPK/BMP/Smad pathway

The present study aimed to assess the effects of therapy with adiponectin (APN) gene-modified adipose-derived stem cells (ADSCs) on pulmonary arterial hypertension (PAH) in rats and the underlying cellular and molecular mechanisms. ADSCs were successfully isolated from the rats and characterized. ADSCs were effectively infected with the green fluorescent protein (GFP)-empty (ADSCs-V) or the APN-GFP (ADSCs-APN) lentivirus and the APN expression was evaluated by ELISA. Sprague-Dawley rats were administered monocrotaline (MCT) to develop PAH. The rats were treated with MCT, ADSCs, ADSCs-V and ADSCs-APN. Then ADSCs-APN in the lung were investigated by confocal laser scanning microscopy and western blot analysis. Engrafted ADSCs in the lung were located around the vessels. Mean pulmonary arterial pressure (mPAP) and the right ventricular hypertrophy index (RVHI) in the ADSCs-APN-treated mice were significantly decreased as compared with the ADSCs and ADSCs-V treatments. Pulmonary vascular remodeling was assessed. Right ventricular (RV) function was evaluated by echocardiography. We found that pulmonary vascular remodeling and the parameters of RV function were extensively improved after ADSCs-APN treatment when compared with ADSCs and ADSCs-V treatment. Pulmonary artery smooth muscle cells (PASMCs) were isolated from the PAH rats. The antiproliferative effect of APN on PASMCs was assayed by Cell Counting Kit-8. The influence of APN and specific inhibitors on the levels of bone morphogenetic protein (BMP), adenosine monophosphate activated protein kinase (AMPK), and small mothers against decapentaplegia (Smad) pathways was detected by western blot analysis. We found that APN suppressed the proliferation of PASMCs isolated from the PAH rats by regulating the AMPK/BMP/Smad pathway. This effect was weakened by addition of the AMPK inhibitor (compound C) and BMP2 inhibitor (noggin). Therefore, combination treatment with ADSCs and APN effectively attenuated PAH in rats by inhibiting PASMC proliferation and regulating the AMPK/BMP/Smad pathway.

Pulmonary Hypertension Associated with Idiopathic Pulmonary Fibrosis: Current and Future Perspectives

Pulmonary hypertension (PH) is commonly present in patients with chronic lung diseases such as Chronic Obstructive Pulmonary Disease (COPD) or Idiopathic Pulmonary Fibrosis (IPF) where it is classified as Group III PH by the World Health Organization (WHO). PH has been identified to be present in as much as 40% of patients with COPD or IPF and it is considered as one of the principal predictors of mortality in patients with COPD or IPF. However, despite the prevalence and fatal consequences of PH in the setting of chronic lung diseases, there are limited therapies available for patients with Group III PH, with lung transplantation remaining as the most viable option. This highlights our need to enhance our understanding of the molecular mechanisms that lead to the development of Group III PH. In this review we have chosen to focus on the current understating of PH in IPF, we will revisit the main mediators that have been shown to play a role in the development of the disease. We will also discuss the experimental models available to study PH associated with lung fibrosis and address the role of the right ventricle in IPF. Finally we will summarize the current available treatment options for Group III PH outside of lung transplantation.

Therapeutic potential of adipose stem cell-derived conditioned medium against pulmonary hypertension and lung fibrosis

BACKGROUND AND PURPOSE

Pulmonary hypertension (PH) and pulmonary fibrosis (PF) are life threatening cardiopulmonary diseases. Existing pharmacological interventions have failed to improve clinical outcomes or reduce disease-associated mortality. Emerging evidence suggests that stem cells offer an effective treatment approach against various pathological conditions. It has been proposed that their beneficial actions may be mediated via secretion of paracrine factors. Herein, we evaluated the therapeutic potential of conditioned media (CM) from adipose stem cells (ASCs) against experimental models of PH and PF.

EXPERIMENTAL APPROACH

Monocrotaline (MCT) or bleomycin (Bleo) was injected into male Sprague-Dawley rats to induce PH or PF respectively. A subset of MCT and Bleo animals were treated with ASCs or CM. Echocardiographic and haemodynamic measurements were performed at the end of the study. Lung and heart tissues were harvested for RNA, protein and histological measurements.

KEY RESULTS

CM treatment attenuated MCT-induced PH by improving pulmonary blood flow and inhibiting cardiac remodelling. Further, histological studies revealed that right ventricular fibrosis, pulmonary vessel wall thickness and pericyte distribution were significantly decreased by CM administration. Likewise, CM therapy arrested the progression of PF in the Bleo model by reducing collagen deposition. Elevated expression of markers associated with tissue remodelling and inflammation were significantly reduced in both PF and PH lungs. Similar results were obtained with ASCs administration.

CONCLUSIONS AND IMPLICATIONS

Our study indicates that CM treatment is as effective as ASCs in treating PH and PF. These beneficial effects of CM may provide an innovative approach to treat cardiopulmonary disorders.

(1)H NMR-Based Analysis of Serum Metabolites in Monocrotaline-Induced Pulmonary Arterial Hypertensive Rats

AIMS

To study the changes of the metabolic profile during the pathogenesis in monocrotaline (MCT) induced pulmonary arterial hypertension (PAH).

METHODS

Forty male Sprague-Dawley (SD) rats were randomly divided into 5 groups (n = 8, each). PAH rats were induced by a single dose intraperitoneal injection of 60 mg/kg MCT, while 8 rats given intraperitoneal injection of 1 ml normal saline and scarified in the same day (W0) served as control. Mean pulmonary arterial pressure (mPAP) was measured through catherization. The degree of right ventricular hypertrophy and pulmonary hyperplasia were determined at the end of first to fourth weeks; nuclear magnetic resonance (NMR) spectra of sera were then acquired for the analysis of metabolites. Principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) were used to discriminate different metabolic profiles.

RESULTS

The prominent changes of metabolic profiles were seen during these four weeks. Twenty specific metabolites were identified, which were mainly involved in lipid metabolism, glycolysis, energy metabolism, ketogenesis, and methionine metabolism. Profiles of correlation between these metabolites in each stage changed markedly, especially in the fourth week. Highly activated methionine and betaine metabolism pathways were selected by the pathway enrichment analysis.

CONCLUSIONS

Metabolic dysfunction is involved in the development and progression of PAH.