There is no consensus regarding the strategy for managing the regional lymph nodes in patients with local breast cancer recurrence. This paper reviews the updated data on re-sentinel lymph node ...biopsy (re-SLNB) after previous surgery. The identification rate of re-SLNB varied from 29 to 100 % (mean 67 %). The success rate of re-SLNB depends on the method used for the previous axillary surgery and the number of lymph nodes harvested. Re-SLNB may be feasible even after mastectomy. A relationship between post-operative radiotherapy and identification of re-SLNB was not seen. A longer disease-free interval may correlate with a lower identification rate, but this finding is not definitive. Based on data regarding back-up dissection after re-SLNB, the accuracy of re-SLNB may be as good as SLNB in primary cases. Altered lymphatic drainage was reported in 2–89 % (mean 32 %) of cases. Because the altered lymphatic drainage can be detected only by lymphoscintigraphy, the radioisotope method, followed by lymphoscintigraphy, should be used. There are not many reported cases of axillary recurrence after re-SLNB, and the follow-up periods have been short. Because re-SLNB cases have a wide variety of backgrounds, it is necessary to accumulate a larger number of cases and to obtain data from longer follow-up period in order to make clear recommendations.
Abstract Ischemic heart diseases are a major global cause of death, and despite timely revascularization, heart failure due to ischemia-hypoxia reperfusion (IH/R) injury remains a concern. The study ...focused on the role of Early Growth Response 1 (EGR1) in IH/R-induced apoptosis in human cardiomyocytes (CMs). Human induced pluripotent stem cell (hiPSC)-derived CMs were cultured under IH/R conditions, revealing higher EGR1 expression in the IH/R group through quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB). Immunofluorescence analysis (IFA) showed an increased ratio of cleaved Caspase-3-positive apoptotic cells in the IH/R group. Using siRNA for EGR1 successfully downregulated EGR1, suppressing cleaved Caspase-3-positive apoptotic cell ratio. Bioinformatic analysis indicated that EGR1 is a plausible target of miR-124-3p under IH/R conditions. The miR-124-3p mimic, predicted to antagonize EGR1 mRNA, downregulated EGR1 under IH/R conditions in qRT-PCR and WB, as confirmed by IFA. The suppression of EGR1 by the miR-124-3p mimic subsequently reduced CM apoptosis. The study suggests that treatment with miR-124-3p targeting EGR1 could be a potential novel therapeutic approach for cardioprotection in ischemic heart diseases in the future.
MicroRNA-145 (miR-145) reportedly alters the phenotype of vascular smooth muscle cells (VSMCs) from a proliferative to a contractile state. So far, viral or plasmid vectors have been experimentally ...used to transduce microRNAs into VSMCs. We hypothesized that a simple ex vivo microRNA delivery system using miR–145-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA NPs) could control the VSMC phenotype and prevent intimal hyperplasia.
Jugular vein grafts of male Japanese white rabbits were soaked in phosphate-buffered saline, control microRNA (cont-miR)-loaded PLGA NP solution or miR–145-loaded PLGA NP solution for 30 minutes (n = 8 for each). Vein grafts were implanted in the ipsilateral carotid artery and assessed 2 weeks after the implantation.
Quantitative polymerase chain reaction analysis showed significantly higher miR-145 expression in the miR–145-treated group. The neointimal area was significantly smaller in the miR–145-treated group (phosphate-buffered saline-treated vs cont–miR-treated vs miR–145-treated group; 1.63 ± 0.52 mm2 vs 1.67 ± 0.49 mm2 vs 0.88 ± 0.34 mm2, respectively; P < .01 for the miR–145-treated vs the cont–miR-treated group). In the miR–145-treated group, Ki–67-positive cells were significantly fewer, indicating lower VSMC proliferation. An inflammation-related molecule, CD40 expression was significantly reduced by miR–145-loaded PLGA NP treatment.
Local and sustained release of miR-145 by PLGA NPs attenuated intimal hyperplasia in the rabbit model by maintaining VSMCs in a contractile state. This simple ex vivo miR-145 delivery system would be promising toward broader clinical application.
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Incorporation of surrounding tissues after implantation of synthetic vascular prostheses potentially varies in accordance with implanted prostheses. To evaluate post-implant tissue incorporation, we ...examined surgical, histological and ultrastructural findings after implantation in animal models. Three types of commercially available prostheses were tested (Gelweave™; Group G, J Graft SHIELD NEO
®
; Group J and Triplex
®
; Group T). Prostheses were implanted into Sprague–Dawley rats subcutaneously or sutured on abdominal aorta of Japanese white rabbits. The tissues were surgically examined for adhesion and were subjected to histological evaluations for cellular and tissue infiltration and ultrastructural observations by scanning electron microscopy (SEM). Group G exhibited less tendency in adhesion formation in early phase (rat: G vs J,
P
< 0.0001; G vs T,
P
< 0.0001/rabbit: G vs J,
P
< 0.0001; G vs T,
P
= 0.059). In late phase, Group J showed highest adhesion (rat: G vs J,
P
= 0.0004; J vs T,
P
= 0.015/rabbit: G vs J,
P
= 0.0015; J vs T,
P
= 0.0044). In group G, a gap was observed between implants and surrounding tissues forming capsulation, whereas other groups exhibited tissue infiltration inside of the implants wall which were also confirmed by SEM. The tissue permeation toward the implants and adhesion was positively correlated (
P
< 0.0001). Surrounding tissue conformation varied in accordance with the type of prostheses. It is desirable to elucidate characteristics of each prosthesis to select suitable grafts for each patient to achieve a better surgical outcome.
Autologous vascular grafts are widely used in revascularization surgeries for small caliber targets. However, the availability of autologous conduits might be limited due to prior surgeries or the ...quality of vessels. Xenogeneic decellularized vascular grafts from animals can potentially be a substitute of autologous vascular grafts. Decellularization with high hydrostatic pressure (HHP) is reported to highly preserve extracellular matrix (ECM), creating feasible conditions for recellularization and vascular remodeling after implantation. In the present study, we conducted xenogeneic implantation of HHP-decellularized bovine vascular grafts from dorsalis pedis arteries to porcine carotid arteries and posteriorly evaluated graft patency, ECM preservation and recellularization. Avoiding damage of the luminal surface of the grafts from drying significantly during the surgical procedure increased the graft patency at 4 weeks after implantation (P = 0.0079). After the technical improvement, all grafts (N = 5) were patent with mild stenosis due to intimal hyperplasia at 4 weeks after implantation. Neither aneurysmal change nor massive thrombosis was observed, even without administration of anticoagulants nor anti-platelet agents. Elastica van Gieson and Sirius-red stainings revealed fair preservation of ECM proteins including elastin and collagen after implantation. The luminal surface of the grafts were thoroughly covered with von Willebrand factor-positive endothelium. Scanning electron microscopy of the luminal surface of implanted grafts exhibited a cobblestone-like endothelial cell layer which is similar to native vascular endothelium. Recellularization of the tunica media with alpha-smooth muscle actin-positive smooth muscle cells was partly observed. Thus, we confirmed that HHP-decellularized grafts are feasible for xenogeneic implantation accompanied by recellularization by recipient cells.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Blood vessels are essential components for many tissues and organs. Thus, efficient induction of endothelial cells (ECs) from human pluripotent stem cells is a key method for generating higher tissue ...structures entirely from stem cells. We previously established an EC differentiation system with mouse pluripotent stem cells to show that vascular endothelial growth factor (VEGF) is essential to induce ECs and that cyclic adenosine monophosphate (cAMP) synergistically enhances VEGF effects. Here we report an efficient and robust EC differentiation method from human pluripotent stem cell lines based on a 2D monolayer, serum-free culture. We controlled the direction of differentiation from mesoderm to ECs using stage-specific stimulation with VEGF and cAMP combined with the elimination of non-responder cells at early EC stage. This "stimulation-elimination" method robustly achieved very high efficiency (>99%) and yield (>10 ECs from 1 hiPSC input) of EC differentiation, with no purification of ECs after differentiation. We believe this method will be a valuable technological basis broadly for regenerative medicine and 3D tissue engineering.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract Objective Inflammation-mediated elastin destruction in the aortic medial layer is related to progression of abdominal aortic aneurysm (AAA). Epigallocatechin-3-gallate (EGCG), a major ...component of green tea polyphenols, reportedly increases elastin synthesis in vitro and may possess anti-inflammatory effects. We used a rat model to investigate whether EGCG could prevent AAA progression. Methods AAA was induced with administration of intraluminal elastase and extraluminal CaCl2 in male rats. Rats were randomly divided into a control group (n = 30) and an EGCG group (n = 30). In the EGCG group, an EGCG solution (20 mg/d) was administered orally to each rat from 2 weeks before AAA induction and continued 4 weeks beyond induction. Results The abdominal aortic diameter was significantly smaller in the EGCG group than in the control group on day 28 (2.9 ± 0.2 vs 2.3 ± 0.1 mm; P < .0001). The medial layer wall thickness and elastin content were significantly greater in the EGCG group than in the control group on day 28 (68.4 ± 13.6 vs 46.7 ± 13.4 μm P < .001 and 20.3 ± 4.6 vs 9.5 ± 3.6% P < .0001, respectively). Gene expression levels of tropoelastin and lysyl oxidase were significantly higher in the EGCG group immediately before AAA induction, indicating promoted elastoregeneration by EGCG administration (tropoelastin: 0.59 ± 0.36 control vs 1.24 ± 0.36 EGCG P < .05, lysyl oxidase: 0.77 ± 0.45 control vs 1.34 ± 0.4 EGCG P < .05) (fold increase). Gene expression levels of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1β, were significantly downregulated in the EGCG group (1.82 ± 0.71 vs 0.97 ± 0.59 P < .05 and 3.91 ± 3.24 vs 0.89 ± 0.59 P < .05, respectively). On day 7, gene expression levels and gelatinolytic activity of matrix metalloproteinase 9 were significantly lower in the EGCG group (1.41 ± 0.86 vs 0.51 ± 0.42 P < .05 and 1.00 ± 0.17 vs 0.29 ± 0.12 P < .0001, respectively), whereas gene expression levels of tissue inhibitors of metalloproteinase-1 were significantly higher in the EGCG group (0.96 ± 0.11 vs 1.14 ± 0.09; P < .05). Conclusions EGCG attenuated AAA progression in a rat model by preserving the aortic thickness and elastin content of the medial layer through regeneration of elastin, as mediated by anti-inflammatory effects, and subsequent reduction of matrix metalloproteinase activity.
Abstract
OBJECTIVES
Excessive and chronic inflammation after a myocardial infarction (MI) is associated with left ventricular remodelling and impaired cardiac function. Among inflammatory cells, ...macrophages play a critical role in polarizing proinflammatory M1 or the reparative M2 subtype. Pioglitazone (PGZ) is reported to regulate macrophage polarization to the M2 subtype. Our goal was to validate the therapeutic effects and the mechanisms of PGZ utilizing a drug delivery system.
METHODS
Poly L-lactic-co-glycolic acid microspheres (MS) incorporating PGZ were prepared. To validate the therapeutic potential of PGZ-MS, Sprague-Dawley rats were subjected to permanent left coronary artery ligation to induce an MI. Placebo-MS (100 μg) or PGZ-MS (100 μg) was injected to the infarct region just after induction. Cardiac function and size were assessed by echocardiography. At 28 days after surgery, the rats were sacrificed, and the excised hearts were evaluated histologically.
RESULTS
Sustained release of PGZ from the PGZ-MS was confirmed in vitro. PGZ-MS significantly rehabilitated cardiac dysfunction after an MI (fractional shortening: MI vs MI+placebo-MS vs MI+PGZ-MS, 24.4 ± 1.1 vs 24.3 ± 1.6 vs 32.2 ± 1.4%; P = 0.0035) with reverse remodelling. Immunohistochemical analyses revealed that PGZ-MS enhanced macrophage polarization (ratio of M2 subtype: 0.39 ± 0.03 vs 0.42 ± 0.02 vs 0.54 ± 0.02; P = 0.0004) and attenuated apoptosis of cardiomyocytes in the ischaemic border zone.
CONCLUSIONS
We confirmed macrophage polarization by sustained release of PGZ, which resulted in amelioration of adverse left ventricular remodelling and cardiac dysfunction. Drug delivery system-based macrophage polarization might serve as a promising strategy in cardiac regenerative therapy for ischaemic heart disease. (241 words)
To realize human induced pluripotent stem cell (hiPSC)-based cardiac regenerative therapy, evidence of therapeutic advantages in human-sized diseased hearts are indispensable. In combination with an ...efficient and simultaneous differentiation of various cardiac lineages from hiPSCs and cell sheet technology, we aimed to generate clinical-sized large cardiac tissue sheets (L-CTSs) and to evaluate the therapeutic potential in porcine infarct heart. We simultaneously induced cardiomyocytes (CMs) and vascular cells vascular endothelial cells (ECs) and vascular mural cells (MCs) from hiPSCs. We generated L-CTSs using 10cm-sized temperature-responsive culture dishes. We induced myocardial infarction (MI) in micromini-pigs (15-25 kg) and transplanted the L-CTSs (Tx) 2 weeks after MI induction (4 sheets/recipient) under immunosuppression (Tx: n = 5, Sham: n = 5). Self-pulsating L-CTSs were approximately 3.5cm in diameter with 6.8×106±0.8 of cells containing cTnT+-CMs (45.6±13.2%), VE-cadherin+-ECs (5.3±4.4%) and PDGFRβ+-MCs (14.4±20.7%), respectively (n = 5). In Tx group, echocardiogram indicated a significantly higher systolic function of the left ventricle (LV) compared to that in sham control (Sham vs Tx: fractional shortening: 24.2±8.6 vs 40.5±9.7%; p<0.05). Ejection fraction evaluated by left ventriculogram was significantly higher in Tx group (25.3±6.2% vs 39.8±4.2%; p<0.01). Speckle tracking echocardiogram showed a significant increase of circumference strain in infarct and border regions after transplantation. Fibrotic area was significantly lower in Tx group (23.8±4.5 vs 15.9±3.8%; P<0.001). Capillary density in the border region was significantly higher in Tx group (75.9±42.6/mm2 vs 137.4±44.8/mm2, p<0.001). These data indicate that the L-CTS transplantation attenuated LV remodeling. L-CTSs potentially restore cardiac dysfunction of human-sized infarct heart.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract Background Cardiopulmonary bypass (CPB) may induce systemic inflammatory responses causing acute lung injury (ALI). Recombinant human soluble thrombomodulin (rTM) is reported to attenuate ...the secretion of inflammatory cytokines and the high-mobility group box 1 (HMGB1) protein, which is critical in controlling systemic inflammation and apoptosis. We investigated the protective effects of rTM on CPB-induced lung injury in a rat model. Methods Eighteen male, Sprague–Dawley rats were divided into three groups: Sham, control (CPB alone), and rTM (CPB + rTM). CPB was conducted in the control group and the rTM group. A bolus of rTM (3 mg/kg) was administered to the rTM group rats before CPB establishment. Results The PaO2 /FiO2 ratio only dropped markedly from before CPB in the control group (p < 0.001). Serum TNF-α, IL-6, and HMGB1 levels were significantly higher in the control group after CPB. Pathological study revealed significantly more severe congestion, alveolar hemorrhage, neutrophil accumulation, and edema, and the number of lung cells expressing HMGB1 increased in the control group. The mRNA expression levels of TNF-α, IL-6, IL-1β, and HMGB1 in the control group were significantly higher than those in other groups. According to Western blot analysis, nuclear factor-kappa B p65 in lung tissue was significantly downregulated in the rTM group. The number of apoptotic cells and the protein of cleaved Caspase-3 were reduced in the rTM group. Conclusions These results suggest that rTM prevents ALI through attenuating inflammation and apoptosis during and after CPB in a rat model.
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