[Research Progress in Promotion of Tissue Regeneration and Reconstruction with Exosomes Derived from Mesenchymal Stem Cells].

In regenerative medicine, stem cell therapy is an effective strategy for tissue regeneration and has a positive therapeutic effect on the regeneration and repair of defective tissues. In recent years, a series of studies have shown that the positive effects of stem cell therapy are mediated by exosomes released by the paracrine action of mesenchymal stem cells. Researchers have thus proposed a novel treatment strategy to use stem-cell-derived exosomes alone for tissue regeneration and repair, and affirmed through studies that the effects achieved were comparable to those of stem-cell-based therapies. Therefore, as a promising treatment strategy, exosome-based tissue regeneration treatment measures have been extensively studied. In this review, we discussed the latest knowledge of exosomes and the research progress in the regeneration and repair of related connective tissues, including the regeneration of bones, cartilage, skin, spinal cord and tendons, and briefly discussed the corresponding mechanisms. In addition, the challenges and prospects of tissue regeneration and repair based on mesenchymal stem cell exosomes were discussed.

Clinical outcomes of percutaneous or surgical closure of ruptured sinus of Valsalva aneurysm.

OBJECTIVE: To evaluate the clinical efficacy, safety, and long-term outcomes of percutaneous closure (PC) and surgical repair of ruptured sinus of Valsalva aneurysm (RSVA). METHODS: Eighty-five consecutive patients with RSVA were included in this study. Patients were considered candidates for PC if they met the criterion, surgical repair was performed on patients who were unsuitable or failed PC. Of them, 30 patients underwent PC, while the other 55 patients had surgical repair. RESULTS: RSVA was successfully occluded in 29 of 30 patients who were treated by PC. The mean narrowest diameter at the ruptured site was 6.45 ± 1.60 mm measured by aortography. One patient developed serious occluder-related aortic regurgitation and underwent surgery. The success rate of the interventional approach was 96.7%. In the surgical group, 23 patients underwent repair of combined RSVA and ventricular septal defect. The hospital mortality rate of the surgical approach was 3.57%. During a median follow-up of 83 months (8-152 months), the improvement in NYHA functional class in the PC group was significantly greater than those in the surgical group (P < .01). One patient died of infective endocarditis in the surgical group. There were no further serious complications. CONCLUSIONS: PC is a safe alternative to surgical repair for patients with isolated RSVA. Surgical repair is more suitable for those who have multiple cardiac lesions requiring surgical treatment or failed PC.

The unique calcium chelation property of poly(vinyl phosphonic acid-co-acrylic acid) and effects on osteogenesis in vitro.

There is a clear clinical need for a bioactive bone graft substitute. Poly(vinyl phosphonic acid-co-acrylic acid) (PVPA-co-AA) has been identified as a promising candidate for bone regeneration but there is little evidence to show its direct osteogenic effect on progenitor or mature cells. In this study mature osteoblast-like cells (SaOS-2) and human bone marrow-derived mesenchymal stem cells (hBM-MSCs) were cultured with PVPA-co-AA polymers with different VPA:AA ratio and at different concentrations in vitro. We are the first to report the direct osteogenic effect of PVPA-co-AA polymer on bone cells and, more importantly, this effect was dependent on VPA:AA ratio and concentration. Under the optimized conditions, PVPA-co-AA polymer not only has an osteoconductive effect, enhancing SaOS-2 cell mineralization, but also has an osteoinductive effect to promote hBM-MSCs' osteogenic differentiation. Notably, the same PVPA-co-AA polymer at different concentrations could lead to differential osteogenic effects on both SaOS-2 and hBM-MSCs in vitro. This study furthers knowledge of the PVPA-co-AA polymer in osteogenic studies, which is critical when utilizing the PVPA-co-AA polymer for the design of novel bioactive polymeric tissue engineering scaffolds for future clinical applications. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 168-179, 2018.

Acute effects of Rho-kinase inhibitor fasudil on pulmonary arterial hypertension in patients with congenital heart defects.

BACKGROUND: We investigated the acute vasodilator effects of i.v. fasudil, a specific Rho-kinase inhibitor, on pulmonary circulation in patients with congenital heart defects (CHD) and severe pulmonary arterial hypertension (PAH). METHODS AND RESULTS: Thirty-five patients (34.23±12.10 years old) with CHD and severe PAH were consecutively enrolled. All patients underwent heart catheterization. At baseline and 30 min after initiation of i.v. fasudil, the following hemodynamic parameters were measured and calculated: right atrial pressure, pulmonary and systemic artery pressure (PAP and SAP), pulmonary and systemic vascular resistance, pulmonary-to-systemic blood pressure ratio (Pp/Ps), pulmonary-to-systemic blood flow ratio (Qp/Qs), cardiac index (CI) and artery oxygen saturation (SaO2). After fasudil treatment, marked decrease in mean PAP (mPAP), pulmonary vascular resistance (PVR), total pulmonary resistance, pulmonary-to-systemic vascular resistance ratio (Rp/Rs) and mean Pp/Ps (mPp/Ps) was found, while Qp/Qs increased significantly without affecting CI and SAP. mPAP, PVR, Rp/Rs and Qp/Qs tended to be improved more significantly in the post-tricuspid shunt group compared with the pre-tricuspid shunt group. CONCLUSIONS: Fasudil was well tolerated in patients with CHD and severe PAH, and significantly reduced PAP and PVR without affecting CI, SAP or SaO2.

Modeled methylmercury exposure and risk from rice consumption for vulnerable populations in a traditional fish-eating area in China.

The circulation of rice from contaminated areas could escalate exposure risk from a local problem to a national issue and affect a wider population beyond the region of origin, as confirmed by the "Poison Rice Incident" in May 2013 in Guangzhou, China. In the present study, the authors established a food chain model based on the aquivalence method to identify major sources of methylmercury (MeHg), estimate the levels of MeHg, and quantify exposure to MeHg via rice and aquatic food consumption. Different types of organism samples from the Haihe River also were collected to verify the calculated values. The MeHg intake in pregnant women was 1529.1 ng/d from the aquatic food chain and as high as 2804.0 ng/d from rice, although the intake varied among scenarios. The maximum possible MeHg concentration in the blood of pregnant women was 5.21 µg/L, higher than the threshold value of MeHg recommended by the US Environmental Protection Agency (4.4 µg/L), which indicated that pregnant women could face risk from MeHg exposure. The authors also assessed the risk of MeHg exposure in pregnant women and their breastfed infants using a new index, HQEquivalent . In 4 scenarios, the HQEquivalent indices ranged from 0.42 to 1.18 for pregnant women and from 0.29 to 0.83 for breastfed infants.

Trophic activity of human P2X7 receptor isoforms A and B in osteosarcoma.

The P2X7 receptor (P2X7R) is attracting increasing attention for its involvement in cancer. Several recent studies have shown a crucial role of P2X7R in tumour cell growth, angiogenesis and invasiveness. In this study, we investigated the role of the two known human P2X7R functional splice variants, the full length P2X7RA and the truncated P2X7RB, in osteosarcoma cell growth. Immunohistochemical analysis of a tissue array of human osteosarcomas showed that forty-four, of a total fifty-four tumours (81.4%), stained positive for both P2X7RA and B, thirty-one (57.4%) were positive using an anti-P2X7RA antibody, whereas fifteen of the total number (27.7%) expressed only P2X7RB. P2X7RB positive tumours showed increased cell density, at the expense of extracellular matrix. The human osteosarcoma cell line Te85, which lacks endogenous P2X7R expression, was stably transfected with either P2X7RA, P2X7RB, or both. Receptor expression was a powerful stimulus for cell growth, the most efficient growth-promoting isoform being P2X7RB alone. Growth stimulation was matched by increased Ca(2+) mobilization and enhanced NFATc1 activity. Te85 P2X7RA+B cells presented pore formation as well as spontaneous extracellular ATP release. The ATP release was sustained in all clones by P2X7R agonist (BzATP) and reduced following P2X7R antagonist (A740003) application. BzATP also increased cell growth and activated NFATc1 levels. On the other hand cyclosporin A (CSA) affected both NFATc1 activation and cell growth, definitively linking P2X7R stimulation to NFATc1 and cell proliferation. All transfected clones also showed reduced RANK-L expression, and an overall decreased RANK-L/OPG ratio. Mineralization was increased in Te85 P2X7RA+B cells while it was significantly diminished in Te85 P2X7RB clones, in agreement with immunohistochemical results. In summary, our data show that the majority of human osteosarcomas express P2X7RA and B and suggest that expression of either isoform is differently coupled to cell growth or activity.

Trial occlusion to assess the risk of persistent pulmonary arterial hypertension after closure of a large patent ductus arteriosus in adolescents and adults with elevated pulmonary artery pressure.

BACKGROUND: No method is available to predict whether patients with patent ductus arteriosus (PDA) and severe pulmonary arterial hypertension (PAH) will show persistent postprocedural PAH (PP-PAH) after PDA closure. This study evaluated the usefulness of trial occlusion for predicting PP-PAH after transcatheter PDA closure in patients with severe PAH. METHODS AND RESULTS: Trial occlusion was performed in 137 patients (age ≥12 years) with PDA and severe PAH. All patients undergoing trial occlusion had a mean pulmonary artery pressure ≥45 mm Hg, pulmonary:systemic flow (Qp/Qs) ratio >1.5, and pulmonary:systemic resistance (Rp/Rs) ratio <0.7. A total of 135 patients (98%) showing stable hemodynamics during occlusion trial underwent successful device closure. Linear correlation analysis revealed weak or moderate relationships between the baseline and post-trial pulmonary artery pressures and pulmonary:systemic pressure (Pp/Ps) ratios. Patients were followed up for 1 to 10 years (median: 5 years). PP-PAH (systolic pulmonary artery pressure >50 mm Hg by Doppler echocardiography) was detected in 17 patients (13%), who displayed no significant differences in sex and age compared with patients without PP-PAH. According to discriminant analysis, the strongest discriminators between patients with and without PP-PAH were the baseline left ventricular end-diastolic volume and the baseline and post-trial systolic Pp/Ps ratios. In particular, a post-trial systolic Pp/Ps ratio >0.5 correctly classified 100% of the PP-PAH and non-PAH patients. CONCLUSIONS: Trial occlusion is a feasible method to predict PP-PAH in patients with PDA and severe PAH. A post-trial systolic Pp/Ps ratio >0.5 indicates a high risk of PP-PAH occurrence after device closure.

Promotion of artery occlusion in dogs by percutaneous rotational atherectomy.

BACKGROUND: This study aims to offer experimental data and indirect evidences for the application of percutaneous rotational atherectomy to treat patent ductus arteriosus (PDA). METHODS: Eleven dogs (6 male dogs and 5 female dogs; aged 14-20 months, with an average of 16.7±3.2 months; weight 20-25 kg, with an average of 22.7±2.5 kg) were enrolled in this study. The diameters of the left and right arteries ranged from 3.2 to 4.8 mm (average 3.9±0.6 mm) on percutaneous angiography. Percutaneous rotational atherectomy with proper rotablator (the size was 1-1.5 mm larger than the artery diameter) was performed in the arterial intima. After 4 weeks from percutaneous rotational atherectomy, arteriography was conducted to observe the changes in artery diameter. Then all dogs were sacrificed and the pathologic examination was conducted on the left and right axillary arteries. RESULTS: There were obvious changes with different degrees in 22 arteries, including 8 arteries with complete occlusion and 12 arteries with stenosis (≥2/3, 1/2, and 1/3 stenosis in 4, 4, and 4 arteries, respectively). The occlusion rate was 36.4% and the total effective rate was 90.9%. It was considered failure in other 2 arteries with <1/3 of stenosis. CONCLUSIONS: Percutaneous rotational atherectomy of arterial intima can promote the occlusion of arteries. This has provided a new choice for the treatment of PDA.

Initial experience of occluding special type patent ductus arterioses using the Amplatzer vascular plug.

BACKGROUND: Occluders licensed for clinical use are not fit for some special Krichenko E patent ductus arterioses. The Amplatzer vascular plug I (AVP1) has not been licensed for use for closure of patent ductus arteriose. We report our initial experience to occluding special type patent ductus arterioses with the AVP1-a single lobe device of single layer Nitinol mesh for short vessel landing zones. METHODS: Patients referred with small and long Krichenko E patent ductus arterioses 1 mm to 3 mm in diameter underwent occlusion using AVP1. All cases underwent pre-, intra- and post-procedural echocardiography and chest X-ray at the completion of the procedure, the next day and at a 30-day, 3-month and 6-month follow-up visits. Device sizing for device waist diameter and length was based on aortography. RESULTS: From April 2008 to June 2012, 26 patients with a mean age of (7.6 ± 8.0) years (range 6 months-32 years) and a mean weight of (23.8 ± 14.8) kg (range 7-67 kg) underwent successful patent ductus arteriose closure. The mean ductus diameter was (2.1 ± 0.7) mm (range 1-3 mm). Transpulmonary (22/26) and transaortic approaches (4/26) were used. No persistent patency was observed after 24 hours and after one month. No device displacement, residual flow and iatrogenic coarctation of the aorta were observed after three months and six months. CONCLUSIONS: The AVP1 makes it easy to close some Krichenko E patent ductus arterioses. Smaller delivery catheter profile and symmetric cylindrical device shape allow for use for small and long Krichenko E patent ductus arterioses 1 mm to 3 mm in diameter and small patients through transaortic approaches. Broader experience is required to further delineate device and patient selection as well as to document its long-term efficacy and safety.

Acute hemodynamic responses to adenosine and iloprost in patients with congenital heart defects and severe pulmonary arterial hypertension.

BACKGROUND: Detection of pulmonary vasoreactivity is important for the evaluation of patient with pulmonary arterial hypertension (PAH). The present study aimed to investigate the acute hemodynamic responses to adenosine and iloprost in patients with congenital heart defects (CHDs) and severe PAH. PATIENTS AND METHODS: From Mar 2007 to Nov 2009, 75 patients with severe PAH secondary to left-to-right shunt CHDs underwent acute vasodilator test using aerosolized iloprost (n = 50) or intravenous adenosine (n = 25). The hemodynamics were detected and analyzed. RESULTS: Decreased mean pulmonary arterial pressure (PAP) and pulmonary vascular resistance (PVR) were observed in 39 and 43 patients in the iloprost group, and in 16 and 19 patients in the adenosine group, respectively. However, the mean PAP was higher than 40 mm Hg in both groups. No significant difference was observed in the age and baseline hemodynamics between the patients with the decrease of PVR and mean pulmonary-to-aortic pressure (Pp/Ps) ratio greater than 10% and the remaining patients. Adenosine decreased both PAP and systemic arterial pressure significantly, while iloprost inhalation selectively reduced the PAP and increased the oxygen saturation of femoral arterial blood and the pulmonary-to-systemic flow (Qp/Qs) ratio. Compared with adenosine, iloprost caused a more profound decline in the Pp/Ps ratio, PVR and pulmonary-to-systemic vascular resistance ratio, and increase in the Qp/Qs ratio. CONCLUSIONS: The acute haemodynamic responses to adenosine and iloprost varied among the patients with CHDs and severe PAH. Different to adenosine, inhaled iloprost exerted selective pulmonary vasodilative effects and was beneficial for pulmonary gas exchange.

[Clinical analysis of transcatheter closure of atrial septal defects in elderly patients].

OBJECTIVE: To evaluate the clinical feature of patients with atrial septal defects (ASD) and the safety and efficacy of transcatheter closure of ASD in elderly patients. METHODS: Between May 2000 and June 2010, 82 patients aged (64.5 ± 3.8) years underwent attempted transcatheter ASD closure. Right heart catheterization was performed before intervention. Echocardiography was made at 1 day, 1, 3, 6 months after the procedure. The pre- and post-closure clinical feature, pulmonary artery pressure (PAP) and cardiac function were evaluated. RESULTS: In 82 patients, 37 (45.1%) patients were associated with pulmonary arterial hypertension (PAH). The systolic PAP and mean PAP [(44.1 ± 12.4) mm Hg (1 mm Hg = 0.133 kPa) and (25.2 ± 6.8) mm Hg, respectively] were measured by right heart catheterization before the procedure. One patient was unsuitable for closure because of severe PAH. The remaining 81 patients underwent successful ASD closure without major complications. After closuring, systolic PAP decreased from (52.7 ± 10.3) mm Hg to (31.8 ± 6.3) mm Hg (P < 0.05), and mean PAP descended from (30.9 ± 4.7) mm Hg to (21.8 ± 3.4) mm Hg (P < 0.05) in the 36 patients with PAH. The cardiac function improved post procedure. There were 6 new-onset atrial fibrillations during follow up. CONCLUSIONS: ASD in elderly patients are commonly associated with PAH. Transcatheter ASD closure is safe and effective in the majority of elderly patients.

Biomechanical properties of single chondrocytes and chondrons determined by micromanipulation and finite-element modelling.

A chondrocyte and its surrounding pericellular matrix (PCM) are defined as a chondron. Single chondrocytes and chondrons isolated from bovine articular cartilage were compressed by micromanipulation between two parallel surfaces in order to investigate their biomechanical properties and to discover the mechanical significance of the PCM. The force imposed on the cells was measured directly during compression to various deformations and then holding. When the nominal strain at the end of compression was 50 per cent, force relaxation showed that the cells were viscoelastic, but this viscoelasticity was generally insignificant when the nominal strain was 30 per cent or lower. The viscoelastic behaviour might be due to the mechanical response of the cell cytoskeleton and/or nucleus at higher deformations. A finite-element analysis was applied to simulate the experimental force-displacement/time data and to obtain mechanical property parameters of the chondrocytes and chondrons. Because of the large strains in the cells, a nonlinear elastic model was used for simulations of compression to 30 per cent nominal strain and a nonlinear viscoelastic model for 50 per cent. The elastic model yielded a Young's modulus of 14 ± 1 kPa (mean ± s.e.) for chondrocytes and 19 ± 2 kPa for chondrons, respectively. The viscoelastic model generated an instantaneous elastic modulus of 21 ± 3 and 27 ± 4 kPa, a long-term modulus of 9.3 ± 0.8 and 12 ± 1 kPa and an apparent viscosity of 2.8 ± 0.5 and 3.4 ± 0.6 kPa s for chondrocytes and chondrons, respectively. It was concluded that chondrons were generally stiffer and showed less viscoelastic behaviour than chondrocytes, and that the PCM significantly influenced the mechanical properties of the cells.

Molecular profiling of single cells in response to mechanical force: comparison of chondrocytes, chondrons and encapsulated chondrocytes.

A chondrocyte and its surrounding pericellular matrix (PCM) are defined as a chondron. The PCM plays a critical role in enhancing matrix production, protecting the chondrocyte during loading and transducing mechanical signals. Tissue engineering involves the design of artificial matrices which aim to mimic PCM function for mechanical strength and signalling motifs. We compare the mechanical performance and mechanoresponsiveness of chondrocytes with and without PCM, and encapsulated by alternate adsorption of two oppositely charged polyelectrolytes; chitosan and hyaluronan. Zeta potential measurements confirmed the success of the encapsulation. Encapsulation did not influence chondrocyte viability or metabolic activity. Cells were compressed by micromanipulation with final deformations to 30%, 50% and 70%. Force-displacement data showed that the larger the deformation at the end of compression, the greater the force on the cell. Mechanoresponsiveness of cells was studied by combining single cell PCR with dynamic compression at 20% and 40%. Aggrecan and Type II collagen gene expression were significantly increased in encapsulated chondrocytes and chondrons compared to chondrocytes whereas dynamic compression had no effect on SOX9 or lubricin gene expression. Our results demonstrate that although encapsulation can mimic responses of chondrocytes to biomechanical compression the molecular profile did not reach the enhanced levels observed with chondrons.

Transcatheter closure of congenital coronary artery fistulae: immediate and long-term follow-up results.

BACKGROUND: Transcatheter closure of coronary artery fistulae (CAF) has emerged as an alternative to surgery, but there are no long-term outcome results. OBJECTIVE: We report immediate and long-term results in 24 patients after transcatheter closure of congenital CAF. METHODS: A total of 24 patients aged 5 to 56 years old with congenital CAF underwent attempted percutaneous transcatheter closure using various devices between November 1998 and August 2008. The immediate closure results and clinical follow-up were reviewed. RESULTS: Of the 24 patients, 20 (83.3%) underwent successful transcatheter closure using various devices. An angiogram right after device deployment revealed complete occlusion in 15 patients (75%) and trivial- to mild- residual flow in 5 patients (25%). Four patients (20%) had transient ST-T wave changes after the procedure. The left ventricular end-diastolic volume decreased from 165+/-31.4 mm3 to 128.6+/-24.4 mm3 (P = 0.012) 24 hours after procedure, and the cardiothoracic ratio from 0.57+/-0.02 to 0.53+/-0.01 (P = 0.003). Follow-up was 100% complete and ranged from 3 months to 10 years. There were no early or late deaths. All patients were asymptomatic with complete closure of CAF except 1 patient (5%) who had a recurrence of shunt at 6-month follow-up, which was re-closed by percutaneous technique. CONCLUSION: Transcatheter closure of CAF is feasible and safe in anatomically suitable vessels and is a promising alternative to surgery in most patients.

Gene expression profiles of dynamically compressed single chondrocytes and chondrons.

A chondrocyte produces a hydrated pericellular matrix (PCM); together they form a chondron. Previous work has shown that the presence of the PCM influences the biological response of chondrocytes to loading. The objective of this study was to determine the gene expression profiles of enzymatically isolated single chondrocytes and chondrons in response to dynamic compression. Cartilage specific extracellular matrix components and transcription factors were examined. Following dynamic compression, chondrocytes and chondrons showed variations in gene expression profiles. Aggrecan, Type II collagen and osteopontin gene expression were significantly increased in chondrons. Lubricin gene expression decreased in both chondrons and chondrocytes. Dynamic compression had no effect on SOX9 gene expression. Our results demonstrate a clear role for the PCM in interfacing the mechanical signalling in chondrocytes in response to dynamic compression. Further investigation of single chondrocytes and chondrons from different zones within articular cartilage may further our understanding of cartilage mechanobiology.

[Effects of transcatheter closure of patent ductus arteriosus in 139 adult patients].

OBJECTIVE: To analyze the clinical feature and the effects of transcatheter closure of adult patients with patent ductus arteriosus (PDA). METHODS: Between January 2000 and April 2009, 139 patients [22 male, aged from 40 to 74: (49.8 +/- 6.8) years] with PDA were hospitalized in our hospital. Clinical data and effects of transcatheter closure of PDA were analyzed. RESULTS: There were 64 patients with NYHA classI, 53 with class II, 16 with class III and 6 with class IV before procedure. In 139 patients, pulmonary arterial hypertension (PAH) was found in 107 out of 139 patients (77.0%). Transcatheter PDA closure was not performed in 3 patients due to severe PAH and successfully performed in the remaining 136 patients (97.8%) without major complications. Post procedure aortic angiography evidenced minor residual shunt in 14 cases, small residual shunt in 2 cases and moderate shunt in 1 case. The NYHA class was significantly improved and the PAH significantly reduced [sPAP: (47.3 +/- 23.9) mm Hg (1 mm Hg = 0.133 kPa) vs. (28.1 +/- 12.3) mm Hg, P < 0.01] post procedure. CONCLUSION: PAH and heart failure were commonly associated with PDA in adult patients. Transcatheter PDA closure is safe and effective in these patients except those with severe PAH.