cardiac graft procurement for langendorff perfusion 

Modifiye Langendorff Perfüzyonu ile CVD Araştırmalarının Geliştirilmesi

The field of cardiovascular research has seen important advancements in the diagnosis and treatment of cardiovascular diseases (CVDs). However, despite the general decrease in incidence and mortality rates, CVDs remain the leading cause of death globally1,2. This alarming fact highlights the need for increased research and scientific advancement, which is undoubtedly dependent on the accuracy and predictability of the available research tools. As a result, there is a constant need for innovation, improvement and/or repurposing of the research toolset. For instance, retrograde or Langendorff heart perfusion, a technique available to the field for over a century, can be easily modified to cover a larger scope of scientific needs and achieve a broader range of applications.
The isolation of the cardiac graft from the rest of the organism during Langendorff perfusion provides an important degree of control over a wide array of experimental parameters, including temperature, circulating solution, coronary perfusion pressures, etc.3,4,5,6,7. The manipulation of these parameters facilitates the simulation of a large number of cardiac scenarios that can be leveraged to further scientific advancements5,8,9,10. Among these parameters, perfusion pressure is likely the most overlooked experimental setting11.
During Langendorff, perfusion pressures exhibit a direct correlation with heart rate, peak systolic/diastolic pressures, and oxygen consumption11. This correlation provides direct and precise control over the amount of work produced by the cardiac grafts, which can be adjusted to meet individual experimental needs. Despite this valuable control capability, the field has historically gravitated towards the use of higher perfusion pressures (60-80 mmHg), subjecting all cardiac grafts to high work demand irrespective of experimental needs8,12,13,14,15. The consequences of this unnecessarily high demand for work arise from the overarching principle that overwork tends to result in premature failure. This seems to be particularly true for cardiac grafts perfused via Langendorff, as the non-physiological nature of this method and the lack of recovery support present in vivo seem to exacerbate graft failure. This premature loss of graft function limits perfusion and experimental times significantly. In effect, in circumstances where longer perfusion times are more relevant to the experimental needs (i.e., drug treatments, immunological response analysis, gene editing, graft preservation, etc.), lower cardiac work can be afforded in exchange for increased graft durability.
This protocol demonstrates the feasibility of utilizing lower perfusion pressures (30-35 mmHg) during Langendorff, as well as the significant effect these pose for cardiac graft function over time when compared to higher perfusion pressures (60-80 mmHg). Furthermore, the findings in this manuscript highlight the importance of prioritizing the customization of the wide array of perfusion parameters to better meet experimental needs.

Yazar Spotlight: İlerleyen Kardiyovasküler Araştırma - İyileştirilmiş Deneysel Sonuçlar için Özel Langendorff Perfüzyon Teknikleri

Kemirgen Kardiyak Greftlerin Daha Uzun Perfüzyon Süreleri için Modifiye Langendorff Perfüzyonu

This research aims to highlight the dynamism and broad application of Langendorff perfusion as a research tool and its immense utility in cardiovascular disease research. It also highlights the importance of tailoring the different perfusion parameters, such as flows, pressures, perfusate, and temperature to better fit experimental needs. This protocol offers an alternative approach to the current status quo of Langendorff perfusion.It suggests that using lower than normal perfusion pressures such as 30 to 35 millimeters of mercury instead of the usual 60 to 80 millimeters of mercury could be beneficial for certain types of experiments and could improve overall scientific outcomes of relevant studies. This protocol enhances the significance of Langendorff perfusion as a technique for the cardiovascular research by eliminating the loss of function that is dependent on the technique. Furthermore, it is expected to start a conversation about the best perfusion practices for clinically perfused cardiac grafts, such as those that are being preserved for transplantation.

Langendorff perfüzyonu için kardiyak greft alımı 

cardiac-graft-procurement-for-langendorff-perfusion

Research

JoVE Journal

Bioengineering

Cardiac Graft Procurement for Langendorff Perfusion 

198 Görüntüleme. Başlamak için, refleksler artık gözlenmediğinde anestezi uygulanan fareyi anestezik odadan çıkarın. Cerrahi boşluğa yerleştirin ve yüz maskesi aracılığıyla% 3'te sürekli izofluran verin. Ayak parmağı sıkışma testi yaptıktan sonra, hayvanın penis damarından 30 ünite heparin uygulayın.Fareyi tüm karın ve üst göğüs bölgesi boyunca tıraş edin. Daha sonra kürk talaşını cerrahi alandan çıkarın. Ameliyat sırasında ...

Video: Langendorff perfüzyonu için kardiyak greft alımı 

Modified Langendorff Perfusion for Extended Perfusion Times of Rodent Cardiac Grafts

Despite important advancements in the diagnosis and treatment of cardiovascular diseases (CVDs), the field is in urgent need of increased research and scientific advancement. As a result, innovation, improvement and/or repurposing of the available research toolset can provide improved testbeds for research advancement. Langendorff perfusion is an extremely valuable research technique for the field of CVD research that can be modified to accommodate a wide array of experimental needs. This tailoring can be achieved by personalizing a large number of perfusion parameters, including perfusion pressure, flow, perfusate, temperature, etc. This protocol demonstrates the versatility of Langendorff perfusion and the feasibility of achieving longer perfusion times (4 h) without graft function loss by utilizing lower perfusion pressures (30-35 mmHg). Achieving extended perfusion times without graft damage and/or function loss caused by the technique itself has the potential to eliminate confounding elements from experimental results. In effect, in scientific circumstances where longer perfusion times are relevant to the experimental needs (i.e., drug treatments, immunological response analysis, gene editing, graft preservation, etc.), lower perfusion pressures can be key for scientific success.

This article demonstrates the feasibility of achieving longer perfusion times (4 h) of murine cardiac grafts without function loss by employing lower (30-35 mmHg) than physiological (60-80 mmHg) perfusion pressures during Langendorff.

Despite important advancements in the diagnosis and treatment of cardiovascular diseases (CVDs), the field is in urgent need of increased research and ...

Biyomühendislik

To begin, remove the anesthetized rat from the anesthetic chamber once reflexes are no longer observed. Place it into the surgical space and deliver continuous isoflurane at 3%via face mask. After conducting a toe pinch test, administer 30 units of heparin through the penile vein of the animal.Shave the rat across the entire abdomen and upper chest area. Then remove the fur shavings from the surgical field. Secure each limb with tape to prevent movement during surgery.Now make a horizontal midline incision in the skin of the lower abdomen to expose the abdominal muscles. Then make a second horizontal midline incision through the abdominal muscles to expose the internal organs. Next, expose the sternum.Secure it with a hemostat and retract it cranially to display the liver and portal vein. Using a 16 gauge angiocatheter, insert a catheter into the portal vein and connect a 60 milliliter syringe of heparinized saline to the angiocatheter. Then, create an incision in the inferior vena cava and abdominal aorta for venting.Flush the entire amount of saline through the portal vein. Afterward, make a horizontal cut in the diaphragm, followed by a proximal cut through the ribs on both sides of the sternum to reveal the thoracic cavity. Remove the heart from the cavity and immediately place it on a Petri dish with saline on ice.Then identify the aortic arch. Clamp it with hemostats and expose the descending aorta by clearing any remaining connective tissue. Using dissecting micro scissors, make a horizontal cut halfway across the descending aorta and insert a 14 gauge angiocatheter.Secure the cannula with a suture above the cuff and release the hemostat.

Optimizing Langendorff Perfusion Parameters for Enhanced Cardiac Graft Function and Durability 

To begin set the peristaltic pump's flow to 1.0 milliliters per minute. Weigh the isolated rat's heart and cannula before attaching them to the system. Connect the cannula to the system's connector and start a timer.Once the heart contracts fully increase the flow in 0.2 milliliters per minute increments while monitoring the pressures, stop increasing the flow when the desired pressures are reached, or when a minimum flow of 3.5 milliliters per minute is achieved. Four pressures between 30 and 35 millimeters of mercury. Set the flow to 4.5 milliliters per minute.Then start the Adenosine syringe pump. Using a Luer lock connector, connect the catheter to a pressure sensor and secure the entire setup to a clamp stand. After that, attach a small latex balloon to a balloon catheter with a tapered tip.Using a syringe attached to the top end of the pressure sensor. Fill the balloon, catheter, and pressure sensor with approximately 200 microliters of saline. Then with the help of a sphygmomanometer calibrate the pressure sensor.Next, make a small horizontal incision above the left atrium. Deflate the balloon by drawing back the syringe at the top of the pressure sensor and inserting it into the left ventricle. Afterward start data acquisition and inflate the balloon until the diastolic pressures indicate zero millimeters of mercury.A clear correlation was established between heart rate and perfusion pressures. Notably, heart rate was significantly higher in high pressure hearts compared to low pressure hearts throughout the study with the exception of the initial measurement. There was a significant disparity in left ventricular pulse pressure or LVPP between the groups with high pressure hearts displaying statistically higher LVPP across all time points.Over time high pressure hearts exhibited a progressive decline in function with a noticeable decrease in LVPP after two hours. Conversely, low pressure hearts maintained consistent LVPP throughout the perfusion. High pressure hearts demonstrated superior cardiac function compared to low pressure hearts.