We thank Fred Roberts for exemplary technical support and also appreciate the help from the histology core in Beth Israel Hospital. We thank Brigham Women&#8217;s Hospital Cardiovascular Physiology Core for providing with the instrumentation and the funds for this work. This work was supported in part by a Department of Medicine Sundry Fund.

NOT: Tüm işlemler Amerikan Veteriner Hekimleri Birliği (AVMA) kurallarına uygun olarak farelerde yapılan ve Kurumsal Hayvan Bakım ve Kullanım Komiteleri (IACUC) protokolleri onaylandı. 1. Çalışma Tasarımı <ol><li> Çalışmaya 8-10 haftalık erkek C57BL / 6 fareleri (BW ~ 25 g) kullanın. </li><li> İki gruba fareler (n = 11), aort bantlama için seçilen çalışma grubu Rastgele (n = 8), ve kontrol grubu (n = 3) torakotomi yoluyla sahte ameliyat için. </li><li> Tıbbi sınıf olan tüy dökücü krem ​​kullanarak göğüs saç kaldırarak görüntüleme için hayvan hazırlayın. </li><li> (Roket ucu konisi üzerinden% 100 O 2 ile karışık)% 1 ve% 2.5 izofluran bağlı anestezi aralığında, Gün -1 de temel parametrelerini belirlemek için aort bantlama 24 saat önce birinci ultrason (bölüm 2) yapın. </li><li> Tıbben onaylanmış anestezik ajan seçin (örneğin izofluran) ve indu anestezi (% 2-3 derecesini izlemekCE ve% 1.0 korumak için). NOT: Uygun anestezi normal fizyolojik oranları (yaklaşık 500 atım / dk) kalp atım bakım çok önemlidir. </li><li> Bir pedal çekilme refleksi tepki olarak hayvandan hareket kaybı anestezi derinliği onaylayın. Anestezi altında iken kuruluğu önlemek için göze paralube veteriner merhem kullanın. </li><li> Gün 0 20,21 de ameliyat. </li><li> Aort bantlama için, kemer üzerine yerleştirilen konik 26 G iğne etrafında 7-0 ipek sütür kullanılarak aort Arter. NOT: Cerrahi aort bantlama prosedürleri de dahil olmak üzere deneysel protokol, ilgili Detaylar, daha önce 20,21 tarif edilmiştir. </li><li> Gün (ler) 2, 6 ve 13 yaşında ameliyat sonrası ultrason görüntüleme (bölüm 2) yapın. </li><li> Gün 14 fareler Euthanize ve histolojik değerlendirme için kalpleri hasat. Kalp gibi hayati bir organ uzaklaştırılarak elde edilmiş aşırı dozda pentobarbital kullanılarak hayvanlar öldürülür. Diasto kalpleri Arrestle ve formalin ile sabitleyin. Daha önce 22 tarif edilmiştir kalp hasat yordamı kullanın. </li><li> Tamponlu% 10 formalin solüsyonu ile tüm kalp dokuları Fix. Trichrome boyama için, kesit önce parafin dokuların embed. Daha önce de 14,23 gösterilmiş olan trichrome boyama ayrıntılarını kullanın. </li><li> Çevrimdışı yazılım (bölüm 3) kullanarak verileri analiz. </li></ol> 2. Görüntüleme Protokolü <ol><li> Septal koroner arter Uzun ve kısa eksen görüntüleri (SCA) (B- Modu) <ol><li> Aktif-porta bağlı 40 MHz merkez frekansı ile MS550D prob kullanarak, &quot;kardiyak görüntüleme&quot; uygulama ön ayarı ayarlayın. </li><li> Isıtmalı platformda, ve burun konisi ile kontrol anestezi altında hayvan sırtüstü ile, parasternal uzun eksen görünümü (PSLAX) (Şekil 1A) elde etmek raylı sistemi kullanarak probu yerleştirin. Her zaman hayvan prewarmed platfor sıcak tutulmasını sağlamakm ve vücut sıcaklığı, fizyolojik düzeyde muhafaza edilmektedir. </li><li> (Çentik kaudal bakacak şekilde) prob saat yönünde çevirin böyle prob açısı sol parasternal hat (uzun eksen görünümü) (Şekil 1B) 15 ° olduğunu. </li><li> Ekran (Şekil 1B) merkezinde, SCA, tam uzunlukta uzunlamasına bir görünüm elde etmek için prob y ekseni boyunca hafifçe eğerek sistemi açısını ayarlayın. </li><li> Uygun görülecek (aort kapağı ve pulmoner arter), sine dükkanını mümkün olan en yüksek kare hızı-kullanarak görüntüyü inceledi kez. </li><li> &quot;Xy&quot; kullanarak mikro-manipülatörler (Şekil 1D) eksenlerinde, SCA net görüntüsünü elde etmek için prob konumunu ayarlamak. </li><li> Prob çentikli ucu orta hat (kısa eksen) sol olacak şekilde saat yönünde (Şekil 1C) (çentik kaudal bakacak şekilde) prob 90 ° döndürün. </li></ol></li><li> SCA uzun ve kısa eksen görüntüleri (Renkli Doppler Mode) <ol><li> B Modu görüntü yakalanır veya sine-saklanır sonra, renkli Doppler akustik pencerede (Şekil 2) açmak için klavyedeki renkli Doppler anahtarını tıklatın. NOT: Bu (beyaz ok SCA gösterir) ya uzun (Şekil 2A) ya da kısa eksen (Şekil 2C) koroner arter izole etmek için yardımcı olur. Kırmızı renk gerçek zamanlı olarak görülen ve (uzak aort kapak itibaren) akış yönüne göstergesidir edilir. </li><li> (Görüntü ekranının sağ sarı ok ile gösterilen) odak derinliği, koroner arter merkezinde yatıyor emin olun. </li><li> Veri mümkün olan en yüksek kare hızı (&gt; 100 kare / sn) ile, sine-mağaza tuşunu kullanarak, kaydedilen emin olun. </li></ol></li><li> SCA PW Doppler Görüntüleme (Darbeli-Dalga veya PW Modu) <ol><li> Renkli Doppler modunda iken, (kırmızı ile gösterilen Şekil 2) koroner arter üzerinde sarı-gösterge hattı getirmek için PW tuşuna tıklayın. </li><li> Sarı yerleştirinAkış yönünü paralel bir açı görünümü koroner arter orta PW hattı. Bu hız ölçümleri görüntü elde açısı son derece bağlı olduğunu unutmayın. </li><li> 60 ° veya daha az ve örnek hacmi SCA merkezine doğru akış yakalar akış açısını (PW açı anahtarı) ve PW açı anahtarı olacak şekilde numune hacmi (SV tuşu) ayarlayın. </li><li> % 1 ve% 2.5 izofluran kullanılarak, zirve sistol, (S) ve sistol (D) (Şekil 3A ve 3B), koroner akış hızını göstermektedir dalga formları yakalamak için sine deposu kullanın. </li></ol></li></ol> 3. Veri Hesaplama ve Analizi <ol><li> Hız zamanı Şekil 3A ve 3B gösterilen resimlerden zirve sistolik ve diyastolik hızları elde etmek için ayrılmaz (VTI) aracını seçin. </li><li> Hiperemik (% 2.5 izofluran) zirve diyastolik f oranı olarak koroner akım rezervi indeksi (CFR) hesaplayınbaşlangıca düşük hız (% 1 izofluran) zirve diyastolik akım hızı. </li><li> Zirve sistolik koroner akım hızı / pik diyastolik koroner akım hızı olarak S / D oranı hesaplayın. Başlangıçta oranı (% 1 izofluran) ve hiperemi de (% 2.5 izofluran) belirleyin. </li><li> Böyle FS, FAC, LVM gibi standart kardiyak fonksiyon parametreleri için özel bir yazılım kullanarak veri analizi gerçekleştirmek veya Cheng vallahi kağıdı 2 başvurmak için üreticiden kılavuzlarına bakın. </li></ol>

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The authors report no disclosures.

Bu ultrason tabanlı çalışmada, koroner akım non-invaziv bir değerlendirme tekrarlanabilir canlı deneysel farelerde, gün boyunca, gerçek zamanlı olarak yapıldı; ayrıca, protokol erken bir aşamada bulunan ve miyokard perfüzyon yetersizliği ile ilişkili koroner arter disfonksiyonu tespit potansiyeli gösterdi. Bu yöntem sonuçta kardiyovasküler risk belirlenmesi ve / veya terapötik müdahaleye değerlendirilmesi yanıt klinik bir araç olarak kaldıraçlı olabilir. İlk ola...

Klinik aort darlığı (AS), sol ventrikül (LV) afterload&#39;ı ilerici artışı teşvik bilinmektedir. Bu kronik yükselen hemodinamik yük dengelemek için, LV hipertrofisi (SVH) adaptif cevap 1,2 olarak gelişir. LVH gelişimi sıklıkla koroner mikrosirkülasyondaki anormallikler ile ilişkilidir. Bu mikrovasküler disfonksiyon bu hastalarda 5 kronik iskemi katkıda düşünülmektedir. Koroner akım 3,4 ek olarak, koroner akım rezervi (CFR) koroner arterlerin 1,3 fonksiyonel değişimi temsil eder ve temel akış hızı veya tükürük akış hızı 4,6,7 için hiperemi maksimal akım hızı oranı olarak tanımlanır. CFR AG yeniden 1-3,5-9 sırasında düşer, koroner disfonksiyon 1,10,17 fonksiyonel şiddetinin ölçüde bir indeksi olarak kullanılmıştır. Bu genişlemiş kardiyomiyopati, 10 çeşitli biçimlerde ve ayrıca koroner s şekilde bozuk olduğu bilinentenosis 6. CFR da kötü klinik sonuçlara 12 için prognostik göstergedir. Böyle iskemi veya LVH gibi kardiyak disfonksiyon ortamında LV remodeling da geniş fibrozis, koroner arterlerin 1,2 koroner mikrosirkülasyondaki ve kalınlaşma değişiklikler eşlik eder. Koroner fizyolojisinde Bu değişikliklerin bir sonucu olarak, koroner arter olası yeniden şekillenme vardır. Bu düşük oksijen difüzyon ve miyokard iskemi 1,2,13 yatkınlık neden olabilir LV diyastolik disfonksiyon etkilerini azaltmaya yardımcı olur. Genetiği değiştirilmiş fareler gibi koroner ateroskleroz 5,7,10,12,17 şimdi insan hastalık koşullarını taklit için yaygın olarak yaygın araştırma araçtır. Özellikle farelerde basınç aşırı modeli yaygın 14,17 çalışılmıştır. Trans-aort daralma modeli (TAC) geniş fibroz ve olarak koroner ile ilişkili olduğu gösterilmiştirY darlığı koroner arterlerin medial kalınlaşma ve insanlarda LVH ayar görülene çok benzer koroner akım formları 1,11,17,19 değişiklikleri eşlik eden, kısmen, elde edilen. Bu uzun süreli basınç aşırı yaklaşık 4-8 ​​hafta içinde dekompanse kalp yetmezliğine yol açtığı bilinmekle birlikte, bantlama sonra koroner akım dinamikleri ve erken hastalık ilerlemesi sürecinde bu modellerde akım rezervi, ve farklı aşamalarında etkileri, henüz açıkça tarif edilecek. Farelerin çok sayıda suşları iyi karakterize LDLR dahil olmak üzere araştırma kullanımı, şu anda mevcuttur - / - veya ApoE - / - fareler 10-12, ve bu canlı farelerde 11-15 kardiyovasküler fonksiyonu ve morfolojisi değerlendirmede hassas tekniklerin geliştirilmesini teşvik etmiştir. Bu tür teknikler invaziv umut verici alternatifler sunmak hepsi MRG, PET, kontrast BT, yüksek frekanslı ultrason, ve elektron ışın tomografi 2,9,17,19 dahilkardiyak kateterizasyon ve koroner anjiyografi 12 gibi yöntemler. Ancak, koroner arterlerin çok küçük boyutu ve yüksek kalp hızı (KH) ile farelerde, koroner dolaşım görüntüleme hala birçok mevcut tekniklerin 4,12 için bir teknik sorun oluşturmaktadır. İlginçtir, 15 yaklaşık 30-100 mikron eksenel kararlar sağlayan 50 MHz merkez frekansları yüksek frekanslı dizi tarama kafaları geliştirilmesi de dahil olmak üzere transtorasik Doppler ekokardiyografi (TTDE) alanında teknik ilerlemeler, bir üstel artış olmuştur, 8-40 mm derinliklerinde, ve kare hızlarında fazla 400 / sn kare ele geçirdi. Buna karşılık, TTDE-tabanlı teknikler koroner arterler 5,12 olarak 2 büyük veya daha küçük damarları görüntüleme için bir potansiyel olarak güçlü bir araç olarak ortaya çıkmıştır. Araştırmacılar, küçük a vasculaturenin tanısal görüntüleme çalışmaları yürütmek için izin verdi bir başka kritik avansnimals 11 görüntüleme sırasında kalp ve hayvanların solunum hızını korumak anestezik dikkatle kontrol kullanılmasıdır. Kontrollü anestezi bakım farelerde vazodilatasyon ile ilgili çalışmalar için özellikle önemlidir, ve anestezi etkisi daha da bu bağlamda 10,11 keşfedilmeyi gerekmektedir. İnsanlarda, diğer taraftan, TTDE türetilmiş CFR ölçümleri esas olarak sol ön inen (LAD) koroner arter 5,16 olarak, tıkalı olmayan engel epikardiyal koroner arterlerde değerlendirilmesi için daha yaygın olarak kullanılan bir araç haline gelmiştir. Ancak, CFR ve asemptomatik hastalarda veya istirahatte korunmuş sol ventrikül sistolik fonksiyonu farelerde koroner akım değişiklikleri prognostik rolü çok daha az olmuştur 16 araştırdı. Bu nedenle, çalışmanın amacı, ilk bir basınç aşırı fare modelinde TTDE kullanarak koroner akım değişiklikleri değerlendirmek için, net bir adım-adım protokolü kurmak oldu; İkinci, bu çalışma prognoz işareti incelenmiştirCFR ve tepki koroner akım değişiklikleri ificance bu farelerde aşırı stres baskı yapmak. Biz CFR ve koroner akım TTDE dayalı değerlendirme LV disfonksiyonu önce olabilir koroner fonksiyon bozukluğunun erken tanısında yararlı olabileceğini varsaydık.

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ultrasound based assessment of coronary artery flow and coronary flow reserve using the pressure overload model in mice

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow reserve (CFR) in humans. Reduced CFR is accompanied by marked intramyocardial and pericoronary fibrosis and is used as an indication of the severity of dysfunction. This study explores, step-by-step, the real-time changes measured in the coronary flow velocity, CFR and systolic to diastolic peak velocity (S/D) ratio in the setting of an aortic banding model in mice. By using a Doppler transthoracic imaging technique that yields reproducible and reliable data, the method assesses changes in flow in the septal coronary artery (SCA), for a period of over two weeks in mice, that previously either underwent aortic banding or thoracotomy. 
During imaging, hyperemia in all mice was induced by isoflurane, an anesthetic that increased coronary flow velocity when compared with resting flow. All images were acquired by a single imager. Two ratios, (1) CFR, the ratio between hyperemic and baseline flow velocities, and (2) systolic (S) to diastolic (D) flow were determined, using a proprietary software and by two independent observers. Importantly, the observed changes in coronary flow preceded LV dysfunction as evidenced by normal LV mass and fractional shortening (FS). 
The method was benchmarked against the current gold standard of coronary assessment, histopathology. The latter technique showed clear pathologic changes in the coronary artery in the form of peri-coronary fibrosis that correlated to the flow changes as assessed by echocardiography. 
The study underscores the value of using a non-invasive technique to monitor coronary circulation in mouse hearts. The method minimizes redundant use of research animals and demonstrates that advanced ultrasound-based indices, such as CFR and S/D ratios, can serve as viable diagnostic tools in a variety of investigational protocols including drug studies and the study of genetically modified strains.

Bir kaç zaman noktasında tek bir gözlemci tarafından incelenmiştir (bantlı, n = 8 ve taklit, n = 3), uygun ve tekrar görüntü elde edilmiş olan 11 Fareler: başlangıçta (D-1), D2, D6 ve D13 . Ayrıca, sıkıştırıcı yerinde akış hızı cerrahi (p &lt;0,05) bir gün sonra plasebo farelerin 277,5 ± 10.51 mm / s ile karşılaştırıldığında 110.9 mm / s ± 2.225 olarak ölçülmüştür. hız artışı basıncı aşırı modelinin başarılı kurulması doğrulama oldu. Ayrıca CF hız, CFR, ve S / D o...

Watch this Scientific Journal Video about Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice at JoVE.com

Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice

Coronary flow reserve (CFR) is useful for assessment of myocardial oxygen demand and evaluation of cardiovascular risk. This study establishes a step-by-step transthoracic Doppler echocardiographic (TTDE) method for longitudinal monitoring of the changes in CFR, as measured from coronary artery in mice, under the experimental pressure overload of aortic banding.

Farelerde Basınç Aşırı Modeli Koroner Arter Akış ve Koroner Akım Rezervi Ultrason Dayalı Değerlendirme

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow ...

ultrasound-based-assessment-coronary-artery-flow-coronary-flow

Universidad de Cartagena UDEC

Research

JoVE Journal

Medicine

14.8K Görüntüleme.  Brigham and Women's Hospital, Harvard Medical School. Coronary flow reserve (CFR) is useful for assessment of myocardial oxygen demand and evaluation of cardiovascular risk. This study establishes a step-by-step transthoracic Doppler echocardiographic (TTDE) method for longitudinal monitoring of the changes in CFR, as measured from coronary artery in mice, under the experimental pressure overload of aortic banding.

Video: Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice

Use of a Hanging Weight System for Coronary Artery Occlusion in Mice

Murine studies of acute injury are an area of intense investigation, as knockout mice for different genes are becoming increasingly available 1-38. Cardioprotection by ischemic preconditioning (IP) remains an area of intense investigation. To further elucidate its molecular basis, the use of knockout mouse studies is particularly important 7, 14, 30, 39. Despite the fact that previous studies have already successfully performed cardiac ischemia and reperfusion in mice, this model is technically very challenging. Particularly, visual identification of the coronary artery, placement of the suture around the vessel and coronary occlusion by tying off the vessel with a supported knot is technically difficult. In addition, re-opening the knot for intermittent reperfusion of the coronary artery during IP without causing surgical trauma adds additional challenge. Moreover, if the knot is not tied down strong enough, inadvertent reperfusion due to imperfect occlusion of the coronary may affect the results. In fact, this can easily occur due to the movement of the beating heart.
Based on potential problems associated with using a knotted coronary occlusion system, we adopted a previously published model of chronic cardiomyopathy based on a hanging weight system for intermittent coronary artery occlusion during IP 39. In fact, coronary artery occlusion can thus be achieved without having to occlude the coronary by a knot. Moreover, reperfusion of the vessel can be easily achieved by supporting the hanging weights which are in a remote localization from cardiac tissues.
We tested this system systematically, including variation of ischemia and reperfusion times, preconditioning regiments, body temperature and genetic backgrounds39. In addition to infarct staining, we tested cardiac troponin I (cTnI)
as a marker of myocardial infarction in this model. In fact, plasma levels of cTnI correlated with infarct sizes (R2=0.8). Finally, we could show in several studies that this technique yields highly reproducible infarct sizes during murine IP and myocardial infarction6, 8, 30, 40, 41. Therefore, this technique may be helpful for researchers who pursue molecular mechanisms involved in cardioprotection by IP using a genetic approach in mice with targeted gene deletion. Further studies on cardiac IP using transgenic mice may consider this technique.

A murine model for myocardial ischemia and ischemic preconditioning is an important tool study cardioprotective mechanisms in vivo. Here, we report an easy applicable in situ model for cardiac IP using a hanging-weight system for coronary artery occlusion.

Asma Ağırlık Sistemi Fare Koroner Arter Tıkanıklığı için kullanın

Murine studies of acute injury are an area of intense investigation, as knockout mice for different genes are becoming increasingly available 1-38. ...

Tıp

Coronary Artery Ligation and Intramyocardial Injection in a Murine Model of Infarction

Mouse models are a valuable tool for studying acute injury and chronic remodeling of the myocardium in vivo. With the advent of genetic modifications to the whole organism or the myocardium and an array of biological and/or synthetic materials, there is great potential for any combination of these to assuage the extent of acute ischemic injury and impede the onset of heart failure pursuant to myocardial remodeling. 
Here we present the methods and materials used to reliably perform this microsurgery and the modifications involved for temporary (with reperfusion) or permanent coronary artery occlusion studies as well as intramyocardial injections. The effects on the heart that can be seen during the procedure and at the termination of the experiment in addition to histological evaluation will verify efficacy. 
Briefly, surgical preparation involves anesthetizing the mice, removing the fur on the chest, and then disinfecting the surgical area. Intratracheal intubation is achieved by transesophageal illumination using a fiber optic light. The tubing is then connected to a ventilator. An incision made on the chest exposes the pectoral muscles which will be cut to view the ribs. For ischemia/reperfusion studies, a 1 cm piece of PE tubing placed over the heart is used to tie the ligature to so that occlusion/reperfusion can be customized. For intramyocardial injections, a Hamilton syringe with sterile 30gauge beveled needle is used. When the myocardial manipulations are complete, the rib cage, the pectoral muscles, and the skin are closed sequentially. Line block analgesia is effected by 0.25% marcaine in sterile saline which is applied to muscle layer prior to closure of the skin. The mice are given a subcutaneous injection of saline and placed in a warming chamber until they are sternally recumbent. They are then returned to the vivarium and housed under standard conditions until the time of tissue collection. At the time of sacrifice, the mice are anesthetized, the heart is arrested in diastole with KCl or BDM, rinsed with saline, and immersed in fixative. Subsequently, routine procedures for processing, embedding, sectioning, and histological staining are performed. 
Nonsurgical intubation of a mouse and the microsurgical manipulations described make this a technically challenging model to learn and achieve reproducibility. These procedures, combined with the difficulty in performing consistent manipulations of the ligature for timed occlusion(s) and reperfusion or intramyocardial injections, can also affect the survival rate so optimization and consistency are critical.

Numerous genetic manipulations and/or intramyocardial injections of genes, proteins, cells, and/or biomaterials are superimposed upon the dimension of time in studies of acute ischemia/ reperfusion injury and chronic remodeling in mice. This video illustrates the microsurgical procedures for ischemia/reperfusion, permanent coronary artery ligation, and intramyocardial injection studies.

Enfarktüsü bir murin Model Koroner Arter ligasyon ve intramiyokardiyal Enjeksiyon

Mouse models are a valuable tool for studying acute injury and chronic remodeling of the myocardium in vivo.  With the advent of genetic modifications to ...

Modified Technique for Coronary Artery Ligation in Mice

Myocardial infarction (MI) is one of the most important causes of mortality in humans1-3. In order to improve morbidity and mortality in patients with MI we need better knowledge about pathophysiology of myocardial ischemia. This knowledge may be valuable to define new therapeutic targets for innovative cardiovascular therapies4. Experimental MI model in mice is an increasingly popular small-animal model in preclinical research in which MI is induced by means of permanent or temporary ligation of left coronary artery (LCA)5. In this video, we describe the step-by-step method of how to induce experimental MI in mice.
The animal is first anesthetized with 2% isoflurane. The unconscious mouse is then intubated and connected to a ventilator for artificial ventilation. The left chest is shaved and 1.5 cm incision along mid-axillary line is made in the skin. The left pectoralis major muscle is bluntly dissociated until the ribs are exposed. The muscle layers are pulled aside and fixed with an eyelid-retractor. After these preparations, left thoracotomy is performed between the third and fourth ribs in order to visualize the anterior surface of the heart and left lung. The proximal segment of LCA artery is then ligated with a 7-0 ethilon suture which typically induces an infarct size ~40% of left ventricle. At the end, the chest is closed and the animals receive postoperative analgesia (Temgesic, 0.3 mg/50 ml, ip). The animals are kept in a warm cage until spontaneous recovery.

The surgical procedure used to induce experimental myocardial infarction in mice begins with left thoracotomy between the third and the fourth ribs in order to visualize the anterior surface of the heart and left lung. The left coronary artery is ligated, the chest is closed and the mouse is allowed to recover spontaneously.

Fare Koroner Arter Ligasyonu için Modifiye Tekniği

Myocardial infarction (MI) is one of the most important causes of mortality in humans1-3. In order to improve morbidity and mortality in patients with MI ...

Ultrasound Assessment of Endothelial-Dependent Flow-Mediated Vasodilation of the Brachial Artery in Clinical Research

The vascular endothelium is a monolayer of cells that cover the interior of blood vessels and provide both structural and functional roles. The endothelium acts as a barrier, preventing leukocyte adhesion and aggregation, as well as controlling permeability to plasma components. Functionally, the endothelium affects vessel tone.
Endothelial dysfunction is an imbalance between the chemical species which regulate vessel tone, thombroresistance, cellular proliferation and mitosis. It is the first step in atherosclerosis and is associated with coronary artery disease, peripheral artery disease, heart failure, hypertension, and hyperlipidemia.
The first demonstration of endothelial dysfunction involved direct infusion of acetylcholine and quantitative coronary angiography. Acetylcholine binds to muscarinic receptors on the endothelial cell surface, leading to an increase of intracellular calcium and increased nitric oxide (NO) production. In subjects with an intact endothelium, vasodilation was observed while subjects with endothelial damage experienced paradoxical vasoconstriction.
There exists a non-invasive, in vivo method for measuring endothelial function in peripheral arteries using high-resolution B-mode ultrasound. The endothelial function of peripheral arteries is closely related to coronary artery function. This technique measures the percent diameter change in the brachial artery during a period of reactive hyperemia following limb ischemia.
This technique, known as endothelium-dependent, flow-mediated vasodilation (FMD) has value in clinical research settings. However, a number of physiological and technical issues can affect the accuracy of the results and appropriate guidelines for the technique have been published. Despite the guidelines, FMD remains heavily operator dependent and presents a steep learning curve. This article presents a standardized method for measuring FMD in the brachial artery on the upper arm and offers suggestions to reduce intra-operator variability.

Endothelial dysfunction is associated with numerous disease states and is predictive of adverse cardiovascular events in humans. Flow-mediated vasodilation (FMD) is a non-invasive ultrasound method of evaluating endothelial function. Methodological choices and operator experience may affect results. A systematic approach to FMD in human studies is discussed here.

Klinik Araştırmalarda Brakial Arter Ultrason değerlendirilmesi Endotel Bağımlı Akış Dolayımlı Vazodilatasyon

The vascular endothelium is a monolayer of cells that cover the interior of blood vessels and provide both structural and functional roles. The ...

Permanent Ligation of the Left Anterior Descending Coronary Artery in Mice: A Model of Post-myocardial Infarction Remodelling and Heart Failure

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It is characterized by fluid retention, shortness of breath, and fatigue, in particular on exertion. Heart failure is a growing public health problem, the leading cause of hospitalization, and a major cause of mortality. Ischemic heart disease is the main cause of heart failure.
Ventricular remodelling refers to changes in structure, size, and shape of the left ventricle. This architectural remodelling of the left ventricle is induced by injury (e.g., myocardial infarction), by pressure overload (e.g., systemic arterial hypertension or aortic stenosis), or by volume overload. Since ventricular remodelling affects wall stress, it has a profound impact on cardiac function and on the development of heart failure. A model of permanent ligation of the left anterior descending coronary artery in mice is used to investigate ventricular remodelling and cardiac function post-myocardial infarction. This model is fundamentally different in terms of objectives and pathophysiological relevance compared to the model of transient ligation of the left anterior descending coronary artery. In this latter model of ischemia/reperfusion injury, the initial extent of the infarct may be modulated by factors that affect myocardial salvage following reperfusion. In contrast, the infarct area at 24 hr after permanent ligation of the left anterior descending coronary artery is fixed. Cardiac function in this model will be affected by 1) the process of infarct expansion, infarct healing, and scar formation; and 2) the concomitant development of left ventricular dilatation, cardiac hypertrophy, and ventricular remodelling.
Besides the model of permanent ligation of the left anterior descending coronary artery, the technique of invasive hemodynamic measurements in mice is presented in detail.

Heart failure is the leading cause of hospitalization and a major cause of mortality. A model of permanent ligation of the left anterior descending coronary artery in mice is applied to investigate ventricular remodelling and cardiac dysfunction post-myocardial infarction. The technique of invasive hemodynamic measurements in mice is presented.

Farelerde Sol Ön İnen Koroner Arter Daimi ligasyonu: Post-miyokard Enfarktüs Remodelling ve Kalp Yetmezliği Bir Model

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It ...

Ultrasound Assessment of Flow-Mediated Dilation of the Brachial and Superficial Femoral Arteries in Rats

Arterial vasodilation to increases in wall shear rate is indicative of vascular endothelial function. In humans, the non-invasive measurement of endothelial function can be achieved by employing the flow-mediated dilation technique, typically performed in the brachial or superficial femoral artery. Briefly, a blood pressure cuff placed distal to an ultrasound probe is inflated to a suprasystolic pressure, which results in limb ischemia. After 5 min of occlusion the cuff is deflated, resulting in reactive hyperemia and increases in wall shear rate that signal vasodilatory molecules to be released from the endothelium eliciting vasodilation. Despite the thousands of studies performing flow-mediated dilation in humans, surprisingly, no studies have performed this technique non-invasively in living rats. Considering the recent shift in focus to translational research, the establishment of guidelines for non-invasive measurement of flow-mediated dilation in rats and other rodents would be extremely valuable. In the following article, a protocol is presented for the non-invasive measurement of flow-mediated dilation in brachial and superficial femoral arteries of rats, as those sites are most commonly measured in humans.

Non-invasive assessment of endothelial function in humans can be determined by the flow-mediated dilation technique. Although thousands of studies have used this technique, no study has performed this technique non-invasively in rats. The following article describes non-invasive measurement of flow-mediated dilation in the brachial and superficial femoral arteries of rats.

Flow-Aracılı brakiyal dilatasyonu ve Sıçanlarda Yüzeyel Femoral Arter Ultrason Değerlendirmesi

Arterial vasodilation to increases in wall shear rate is indicative of vascular endothelial function. In humans, the non-invasive measurement of ...

Direct Re-implantation of Left Coronary Artery into the Aorta in Adults with Anomalous Origin of Left Coronary Artery from the Pulmonary Artery (ALCAPA)

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly which is one of leading causes of myocardial ischemia and infarction in children. If left untreated, it results in a 90% mortality rate in the first year of life. In patients who survive to the adulthood, the coronary steal phenomenon and retrograde left-sided coronary flow provide a substrate for chronic subendocardial ischemia, which may lead to left ventricular dysfunction, ischemic mitral regurgitation, malignant ventricular arrhythmias, and sudden cardiac death. The average age of life-threatening presentation is 33 years and of sudden cardiac death 31 years. Therefore, surgical correction is highly recommended as soon as the diagnosis is made, regardless of age. In adult-type ALCAPA originating from the right-facing sinus of the pulmonary artery, direct re-implantation of the ALCAPA into the aorta is the more physiologically sound repair technique to re-establish the dual-coronary perfusion system and is recommended. This protocol describes the technique of direct re-implantation of adult-type ALCAPA into the aorta.

Direct Re-implantation of Left Coronary Artery into the Aorta in Adults with Anomalous Origin of Left Coronary Artery from the Pulmonary Artery ALCAPA

Surgical correction of ALCAPA is highly recommended, regardless of age or the degree of intercoronary collateralization. This protocol presents a technique for the direct re-implantation of adult-type ALCAPA into the aorta to re-establish the dual-coronary perfusion. Whenever feasible, direct re-implantation is preferred to other surgical correction techniques.

Pulmoner Arter Left Koroner arter çıkış anomalileri Erişkin Aort içine Sol Koroner Arter Doğrudan Yeniden implantasyon (ALCAPA)

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly which is one of leading causes of myocardial ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

İzometrik Contractility ölçüm tel Myography kullanarak fare mezenterik arter

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via recanalization of the coronary artery is the most effective strategy for reducing the size of ischemic myocardium. The coronary microvasculature cannot be visualized and imaged&#160;in vivo, but there are several invasive and noninvasive techniques that can be used to assess parameters which depend directly on coronary microvascular function. The endothelial function after ischemia reperfusion can be assessed also at the level of the coronary circulation via the coronary flow reserve (CFR).&#160;In this study, peak velocity of left anterior descending (LAD) coronary arteries was measured in rats in vivo via Transthoracic Doppler Echocardiography during resting and stress challenge (induced by Dobutamine). A normal heart can increase its coronary blood flow up to four times above the resting values during stress induction. Following ischemia reperfusion, we found a significantly diminished CFR, which can be used as a marker of coronary microvascular dysfunction. CFR has opened a window on the importance of microvascular dysfunction and has been shown to predict cardiovascular risk independent of whether the severe obstructive disease is present.

Coronary flow reserve (CFR), is defined as the ratio of maximal coronary blood flow to the resting coronary blood flow. We present a protocol for evaluating CFR in rats via ultrasound, which offers the opportunity to predict cardiovascular risk factors in the absence of obstructive coronary disease.

Farelerde miyokardiyal Iskemi reperfüzyon sonrası koroner akış rezervi değerlendirilmesi

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via ...

Murine Myocardial Infarction Model using Permanent Ligation of Left Anterior Descending Coronary Artery

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine models of MI with permanent ligation of left-anterior descending (LAD) coronary artery closely mimics MI in humans. Murine models benefit from the extensive genetic engineering available nowadays. Here we propose a reproducible murine surgical model of myocardial infarction by permanent LAD coronary ligation. Our technique comprises anesthesia with ketamine/xylazine that can be rapidly reversed by administration of an antagonist, intubation without tracheotomy for mechanical-assisted ventilation, ventilation with application of extrinsic positive end-expiratory pressure (PEEP) to avoid alveolar collapse, a thoracotomy method limiting to the minimum surgical lesions made to skeletal muscles, and lung inflation without thoracentesis. This method is sparsely invasive, reproducible and reduces post-surgery mortality and complications.

Herein we describe a surgical procedure showing how to achieve permanent ligation of the left-anterior descending coronary artery in mice. This model is of high relevance to investigate the pathophysiology of myocardial infarction and the concomitant biological processes.

Sol Anterior İnen Koroner Arterin Kalıcı Ligasyonu ile Murine Miyokard Enfarktüsü Modeli

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine ...