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1.
Theranostics ; 11(16): 7879-7895, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34335970

RESUMO

Rationale: Previous studies have shown that human embryonic stem cell-derived cardiomyocytes improved myocardial recovery when administered to infarcted pig and non-human primate hearts. However, the engraftment of intramyocardially delivered cells is poor and the effectiveness of clinically relevant doses of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in large animal models of myocardial injury remains unknown. Here, we determined whether thymosin ß4 (Tb4) could improve the engraftment and reparative potency of transplanted hiPSC-CMs in a porcine model of myocardial infarction (MI). Methods: Tb4 was delivered from injected gelatin microspheres, which extended the duration of Tb4 administration for up to two weeks in vitro. After MI induction, pigs were randomly distributed into 4 treatment groups: the MI Group was injected with basal medium; the Tb4 Group received gelatin microspheres carrying Tb4; the CM Group was treated with 1.2 × 108 hiPSC-CMs; and the Tb4+CM Group received both the Tb4 microspheres and hiPSC-CMs. Myocardial recovery was assessed by cardiac magnetic resonance imaging (MRI), arrhythmogenesis was monitored with implanted loop recorders, and tumorigenesis was evaluated via whole-body MRI. Results: In vitro, 600 ng/mL of Tb4 protected cultured hiPSC-CMs from hypoxic damage by upregulating AKT activity and BcL-XL and promoted hiPSC-CM and hiPSC-EC proliferation. In infarcted pig hearts, hiPSC-CM transplantation alone had a minimal effect on myocardial recovery, but co-treatment with Tb4 significantly enhanced hiPSC-CM engraftment, induced vasculogenesis and the proliferation of cardiomyocytes and endothelial cells, improved left ventricular systolic function, and reduced infarct size. hiPSC-CM implantation did not increase incidence of ventricular arrhythmia and did not induce tumorigenesis in the immunosuppressed pigs. Conclusions: Co-treatment with Tb4-microspheres and hiPSC-CMs was safe and enhanced the reparative potency of hiPSC-CMs for myocardial repair in a large-animal model of MI.


Assuntos
Infarto do Miocárdio/terapia , Miócitos Cardíacos/metabolismo , Timosina/farmacologia , Animais , Diferenciação Celular , Proliferação de Células , Células Cultivadas , China , Modelos Animais de Doenças , Células Endoteliais/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Infarto do Miocárdio/metabolismo , Miocárdio/patologia , Regeneração , Transplante de Células-Tronco/métodos , Suínos , Timosina/metabolismo , Timosina/fisiologia
2.
J Mol Cell Cardiol ; 144: 15-23, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32387242

RESUMO

AIMS: Recently, we demonstrated that the hearts of neonatal pigs (2-day old) have regenerative capacity, likely driven by cardiac myocyte division, but this potential is lost immediately after postnatal day 3. However, it is unknown if corticosteroid, a broad anti-inflammatory agent, will abrogate the regenerative capacity in the hearts of neonatal pigs. The aim of the current study is to evaluate the effect Dexamethasone (Dex), a broad anti-inflammatory agent, on heart regeneration, structure, and function of the neonatal pigs' post-myocardial infarction (MI). METHODS AND RESULTS: Dex (0.2 mg/kg/day) was injected intramuscularly into the neonatal pig (age: 2 days postnatal) during the first week post-MI. Myocardial scar and left ventricular function were determined by cardiac magnetic resonance (CMR) imaging. Bromodeoxyuridine (BrdU) pulse-chase labeling, histology, immunohistochemistry, and flow cytometry were performed to determine inflammatory cell infiltration, CM cytokinesis, and myocardial fibrosis. Dex injection during the first-week suppressed acute inflammation post-MI in the pig hearts. It inhibited BrdU incorporation to pig CMs and CM cytokinesis via inhibiting aurora-B protein expression which was associated with mature scar formation and thinned walls at the infarct site. CMR imaging showed Dex caused left ventricular aneurysm and poor ejection fraction. CONCLUSIONS: Dex inhibited CM cytokinesis and functional recovery and caused ventricular aneurysm in the hearts of 2-day old pigs post-MI.

3.
Circulation ; 138(24): 2798-2808, 2018 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-30030417

RESUMO

BACKGROUND: The adult mammalian heart has limited ability to repair itself after injury. Zebrafish, newts, and neonatal mice can regenerate cardiac tissue, largely by cardiac myocyte (CM) proliferation. It is unknown whether hearts of young large mammals can regenerate. METHODS: We examined the regenerative capacity of the pig heart in neonatal animals (ages 2, 3, or 14 days postnatal) after myocardial infarction or sham procedure. Myocardial scar and left ventricular function were determined by cardiac magnetic resonance imaging and echocardiography. Bromodeoxyuridine pulse-chase labeling, histology, immunohistochemistry, and Western blotting were performed to study cell proliferation, sarcomere dynamics, and cytokinesis and to quantify myocardial fibrosis. RNA-sequencing was also performed. RESULTS: After myocardial infarction, there was early and sustained recovery of cardiac function and wall thickness in the absence of fibrosis in 2-day-old pigs. In contrast, older animals developed full-thickness myocardial scarring, thinned walls, and did not recover function. Genome-wide analyses of the infarct zone revealed a strong transcriptional signature of fibrosis in 14-day-old animals that was absent in 2-day-old pigs, which instead had enrichment for cytokinesis genes. In regenerating hearts of the younger animals, up to 10% of CMs in the border zone of the myocardial infarction showed evidence of DNA replication that was associated with markers of myocyte division and sarcomere disassembly. CONCLUSIONS: Hearts of large mammals have regenerative capacity, likely driven by cardiac myocyte division, but this potential is lost immediately after birth.


Assuntos
Coração/fisiologia , Infarto do Miocárdio/patologia , Animais , Animais Recém-Nascidos , Citocinese/genética , Ecocardiografia , Fibrose , Imagem Cinética por Ressonância Magnética , Infarto do Miocárdio/diagnóstico por imagem , Miocárdio/patologia , Miócitos Cardíacos/fisiologia , Regeneração , Suínos , Troponina I/análise , Função Ventricular Esquerda
4.
Front Oncol ; 8: 196, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29911072

RESUMO

Glycine decarboxylase (GLDC) gene is frequently upregulated in various types of cancer including lung, prostate and brain. It catabolizes glycine to yield 5,10-methylenetetrahydrofolate, an important substrate in one-carbon metabolism for nucleotide synthesis. In this study, we used exon splicing modulating steric hindrance antisense oligonucleotide (shAON) to suppress GLDC expression and investigated its effect on pyruvate metabolism via hyperpolarized carbon-13 magnetic resonance spectroscopy (MRS). The MRS technique allows us to study in vivo metabolic flux in tumor tissues with/without GLDC-shAON intervention. Here, we show that GLDC-shAON treatment is able to suppress lung cancer cell growth and tumorigenesis, both in vitro and in vivo. The carbon-13 MRS results indicated that the conversion of pyruvate into lactate in GLDC-shAON-treated tumor tissues was significantly reduced, when compared with the control groups. This observation corroborated with the reduced activity of lactate dehydrogenase and pyruvate dehydrogenase in GLDC-shAON-treated lung cancer cells and tumor tissues. Glycolysis stress test showed that extracellular acidification rate was significantly suppressed after GLDC-shAON treatment. Besides lung cancer, the antitumor effect of GLDC-shAON was also observed in brain, liver, cervical, and prostate cancer cell lines. Furthermore, it enhanced the treatment efficacy of cisplatin in lung cancer cells. Taken together, our findings illustrate that pyruvate metabolism decreases upon GLDC inhibition, thereby starving cancer cells from critical metabolic fuels.

5.
Sleep Med ; 9(8): 894-8, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17825609

RESUMO

OBJECTIVE: To study the feasibility of using acoustic signatures in snore signals for the diagnosis of obstructive sleep apnea (OSA). METHODS: Snoring sounds of 30 apneic snorers (24 males; 6 females; apnea-hypopnea index, AHI=46.9+/-25.7events/h) and 10 benign snorers (6 males; 4 females; AHI=4.6+/-3.4events/h) were captured in a sleep laboratory. The recorded snore signals were preprocessed to remove noise, and subsequently, modeled using a linear predictive coding (LPC) technique. Formant frequencies (F1, F2, and F3) were extracted from the LPC spectrum for analysis. The accuracy of this approach was assessed using receiver operating characteristic curves and notched box plots. The relationship between AHI and F1 was further explored via regression analysis. RESULTS: Quantitative differences in formant frequencies between apneic and benign snores are found in same- or both-gender snorers. Apneic snores exhibit higher formant frequencies than benign snores, especially F1, which can be related to the pathology of OSA. This study yields a sensitivity of 88%, a specificity of 82%, and a threshold value of F1=470Hz that best differentiate apneic snorers from benign snorers (both gender combined). CONCLUSION: Acoustic signatures in snore signals carry information for OSA diagnosis, and snore-based analysis might potentially be a non-invasive and inexpensive diagnostic approach for mass screening of OSA.


Assuntos
Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/diagnóstico , Ronco/diagnóstico , Ronco/etiologia , Acústica , Adulto , Índice de Massa Corporal , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polissonografia , Índice de Gravidade de Doença
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