We would like to acknowledge the efforts of Dr Mary-Lou Vallano, Department of Neuroscience and Physiology, for her valuable inputs in the write up for this manuscript.

1.	Rat Surgery for SAH Subject Injected With 0.15 ml Autologous Arterial Blood
<ol>
 <li>The rat is anesthetized using 0.1 mg/kg of Ketamine/Xylazine rodent cocktail and allowed to sit for 5 min.</li>
 <li>Adequate anesthesia is confirmed by reduction in hind limb reflex. </li>
 <li>Using an electronic shaver a neck to nose area of hair around the sub-occipital region is shaved. </li>
 <li>The animal is placed supine on the surgery table and the tail is swabbed with betadine to ensure a sterile incision. </li>
 <li>A straight 1 cm midline incision is taken on the ventral aspect of the tail</li>
 <li>The dissection is extended until the tail artery is identified and isolated. </li>
 <li>Using a sterile 26-gauge catheter, the tail artery is cannulated and 0.15 ml of arterial blood is withdrawn into a syringe.</li>
 <li>A sterile gauze is wrapped around the incision to ensure hemostasis before application of the vetbond to seal the incision. </li>
 <li>The rat is turned prone on the table and the shaved area over the sub-occipital region is swabbed with betadine.</li>
 <li>Using a vertical midline incision access is gained to the cisterna magna. </li>
 <li>Once identified a 25 gauge needle is inserted into the cisterna magna and 0.15 ml of CSF is withdrawn into a syringe to avoid increased intracranial pressures with injection of autologous blood volume. </li>
 <li>Now, the 0.15 ml of blood extracted from the tail artery is injected slowly into the cisterna magna. </li>
 <li>The needle is left in place for 30 sec to ensure clotting in the subarachnoid space and then carefully withdrawn. </li>
 <li>Hemostasis is ensured and the incision is closed using a stapling device.</li>
 <li>The animal is now placed prone on a warming surface with a 20 &deg; head down position for 20 min to allow blood to congeal in the cisterns around the basilar artery. </li>
 <li>Steps 1.1 to 1.15 are repeated during the second surgery 48 hr apart. </li>
</ol>
2.	Rat Surgery for SAH Subject Injected with 0.15 ml Saline
<ol>
 <li>The rat is anesthetized using 0.1 mg/kg of Ketamine/Xylazine rodent cocktail and allowed to sit for 5 min. </li>
 <li>Adequate anesthesia is confirmed by reduction in hind limb reflex. </li>
 <li>Using an electronic shaver a neck to nose area of hair around the sub-occipital region is shaved. </li>
 <li>The animal is placed supine on the surgery table and the tail is swabbed with betadine to ensure a sterile incision. </li>
 <li>A straight 1 cm midline incision is taken on the ventral aspect of the tail </li>
 <li>The dissection is extended until the tail artery is identified and isolated. </li>
 <li>Using a sterile 26-gauge catheter, the tail artery is cannulated and 0.15 ml of arterial blood is withdrawn into a syringe. </li>
 <li>A sterile gauze is wrapped around the incision to ensure hemostasis before application of the vetbond to seal the incision. </li>
 <li>The rat is turned prone on the table and the shaved area over the sub-occipital region is painted with betadine. </li>
 <li>Using a vertical midline incision access is gained to the cisterna magna.</li>
 <li>Once identified a 25 gauge needle is inserted into the cisterna magna and 0.15 ml of CSF is withdrawn into a syringe and the sample is stored. </li>
 <li>Now, the 0.15 ml of normal saline (37 &deg;C) is injected slowly into the cisterna magna. </li>
 <li>The needle is left in place for 30 sec and carefully withdrawn. </li>
 <li>Hemostasis is ensured and the incision is closed using a stapling device. </li>
 <li>The animal is now placed prone on a warming surface with a 20 &deg; head down position for 20 min. </li>
 <li>Steps 2.1 to 2.15 are repeated during the second surgery 48 hr apart. </li>
</ol>
3. Rat Sacrifice
<ol>
 <li>On day 5 after the second surgery, the rats are sacrificed by cardiac perfusion. </li>
 <li>The rat is given a fatal dose (0.2 ml/kg) of Fatal Plus (VORTECH PHARMACEUTICALS LTD., DEARBORN, MI) </li>
 <li>With a vertical midline incision, the abdominal cavity is approached and the peritoneum is opened. </li>
 <li>An anterior thoracotomy is performed and the heart is exposed.</li>
 <li>Using a 26-gauge catheter connected to a phosphate buffer solution (PBS pH 7.4 and at 37 &deg;) the animal is drained of blood and is then perfused with 4% paraformaldehyde.</li>
 <li>After ensuring adequate perfusion, the perfusion is stopped and the rat is brought over to the decapitation table. </li>
 <li>After decapitation, a bone rongeur is used to remove the cranium for brain removal. </li>
 <li>The brain and brainstem are carefully extracted from the cranial vault and placed into a 4% paraformaldehyde solution and stored at 4 &deg;C for 48 hr. </li>
</ol>
4.	Creating Sections to Assess Vasospasm
<ol>
 <li>The rat brain that has now been submerged in 30% sucrose for 4 days is brought to the cryostat for sectioning. </li>
 <li>Once cryoprotected, 12 &mu;M sections are created using the cryostat, with the Anterior Inferior Cerebellar artery (AICA) as the starting point to ensure inter-subject consistency. </li>
 <li>20 sections are created for each animal, ending at the Superior Cerebellar artery (SCA). </li>
 <li>The sections are placed onto a glass slide and assessed for vasospasm using histological methodology</li>
</ol>

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We have nothing to disclose pertaining to this study.

Primates, having a more similar genetic composition and anatomical features to the human, more closely mimic the events of delayed cerebral vasospasm and can more easily undergo non-invasive imaging (MRI and angiography) to monitor arterial changes, than rodents 8. However, primate models are cost-prohibitive and associated with more complex care and ethical issues, than small animal models. Small animal SAH models that have been developed previously have focused on three methods of inducing SAH: 1) Endovascu...

<table border="1">
 <tbody>
 <tr>
 <td>Name of equipment / reagent</td>
 <td>Company</td>
 <td>Catalogue Number</td>
 </tr>
 <tr>
 <td>Male SD rats (250-300 g)</td>
 <td>Taconic</td>
 <td>SD-M</td>
 </tr>
 <tr>
 <td>26 G Catheters</td>
 <td>Webster</td>
 <td>8416683</td>
 </tr>
 <tr>
 <td>25 G Needles</td>
 <td>Buffalo</td>
 <td>305122</td>
 </tr>
 <tr>
 <td>1 cc Syringes</td>
 <td>Central stores</td>
 <td>54245</td>
 </tr>
 <tr>
 <td>Ketamine/Xylazine cocktail</td>
 <td>Animal Care (SUNY)*</td>
 <td>-</td>
 </tr>
 <tr>
 <td>Betadine</td>
 <td>Central stores</td>
 <td>51458</td>
 </tr>
 <tr>
 <td>Sucrose</td>
 <td>Sigma</td>
 <td>S9378-1kg</td>
 </tr>
 <tr>
 <td>Paraformaldehyde</td>
 <td>Sigma</td>
 <td>P6148-500G</td>
 </tr>
 <tr>
 <td>Phosphate buffer solution</td>
 <td>Fisher</td>
 <td>BP-399-4</td>
 </tr>
 <tr>
 <td>Surgical Table</td>
 <td>Harvard</td>
 <td>PY2 72-2590</td>
 </tr>
 <tr>
 <td>OCT Compound (cryoprotection)</td>
 <td>VWR</td>
 <td>25608-930</td>
 </tr>
 <tr>
 <td>Superfrost Slides</td>
 <td>Fisher</td>
 <td>12-550-15</td>
 </tr>
 </tbody>
 </table>
* Synthesized at Department of Laboratory Animal Care, SUNY Upstate Medical University. Add 1 cc [100 mg/ml] of Xylazine to 10 ml [100 mg/ml] of Ketamine.

a low mortality rat model to assess delayed cerebral vasospasm after experimental subarachnoid hemorrhage

Objective: To characterize and establish a reproducible model that demonstrates delayed cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) in rats, in order to identify the initiating events, pathophysiological changes and potential targets for treatment.
Methods: Twenty-eight male Sprague-Dawley rats (250 - 300 g) were arbitrarily assigned to one of two groups - SAH or saline control. Rat subarachnoid hemorrhage in the SAH group (n=15) was induced by double injection of autologous blood, 48 hr apart, into the cisterna magna. Similarly, normal saline (n=13) was injected into the cisterna magna of the saline control group. Rats were sacrificed on day five after the second blood injection and the brains were preserved for histological analysis. The degree of vasospasm was measured using sections of the basilar artery, by measuring the internal luminal cross sectional area using NIH Image-J software. The significance was tested using Tukey/Kramer's statistical analysis.
Results: After analysis of histological sections, basilar artery luminal cross sectional area were smaller in the SAH than in the saline group, consistent with cerebral vasospasm in the former group. In the SAH group, basilar artery internal area (.056 &mu;m &plusmn; 3) were significantly smaller from vasospasm five days after the second blood injection (seven days after the initial blood injection), compared to the saline control group with internal area (.069 &plusmn; 3; p=0.004). There were no mortalities from cerebral vasospasm.
Conclusion: The rat double SAH model induces a mild, survivable, basilar artery vasospasm that can be used to study the pathophysiological mechanisms of cerebral vasospasm in a small animal model. A low and acceptable mortality rate is a significant criterion to be satisfied for an ideal SAH animal model so that the mechanisms of vasospasm can be elucidated 7, 8. Further modifications of the model can be made to adjust for increased severity of vasospasm and neurological exams.

Within the protocols described above, there are several steps that we believe require a better characterization of the model than what has been previously described in the literature. Here we focus on the steps that are essential in order to achieve a reproducible low mortality cerebral vasospasm small animal model and avoid potential pitfalls associated with this model if not done correctly. 
1. Autologous Blood Draw from the Tail Artery: 
Careful placement of the ang...

Watch this Scientific Journal Video about A Low Mortality Rat Model to Assess Delayed Cerebral Vasospasm After Experimental Subarachnoid Hemorrhage at JoVE.com

A Low Mortality Rat Model to Assess Delayed Cerebral Vasospasm After Experimental Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is bleeding that occurs into the subarachnoid space when an aneurysm ruptures. While the morbidity and mortality from this event has been on a decline due to improved treatment approaches, the risk of vasospasm after subarachnoid hemorrhage continues to be the same as it was several years ago. The importance of establishing a comprehensive and reproducible animal model to identify initiating events of cerebral vasospasm has been the focus of research since the first use of rats in an experimental vasospasm model in 1979 by Barry et al. Early work in rats demonstrated that a single injection of autologous blood into the cisterna magna led to acute (within minutes) but not delayed cerebral vasospasm 3, 6, 14. Here we characterize a low mortality SAH rat model that results in reproducible delayed vasospasm.

Objective: To characterize and establish a reproducible model that demonstrates delayed cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) ...

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14.2K vues.  SUNY Upstate Medical University. Hémorragie sous-arachnoïdienne anévrismale (SAH) est le saignement qui se produit dans l'espace sous-arachnoïdien quand une rupture d'anévrisme. Bien que la morbidité et la mortalité de cet événement a été sur un déclin en raison de l'amélioration des méthodes de traitement, le risque de vasospasme après hémorragie sous-arachnoïdienne continue d'être le même que c'était il ya plusieurs années. L'importance d'établir un mod...

Vidéo: A Low Mortality Rat Model to Assess Delayed Cerebral Vasospasm After Experimental Subarachnoid Hemorrhage

Modeling Stroke in Mice - Middle Cerebral Artery Occlusion with the Filament Model

Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are very limited. To meet the need for novel therapeutic approaches, experimental stroke research frequently employs rodent models of focal cerebral ischaemia. Most researchers use permanent or transient occlusion of the middle cerebral artery (MCA) in mice or rats.
Proximal occlusion of the middle cerebral artery (MCA) via the intraluminal suture technique (so called filament or suture model) is probably the most frequently used model in experimental stroke research. The intraluminal MCAO model offers the advantage of inducing reproducible transient or permanent ischaemia of the MCA territory in a relatively non-invasive manner. Intraluminal approaches interrupt the blood flow of the entire territory of this artery. Filament occlusion thus arrests flow proximal to the lenticulo-striate arteries, which supply the basal ganglia. Filament occlusion of the MCA results in reproducible lesions in the cortex and striatum and can be either permanent or transient. In contrast, models inducing distal (to the branching of the lenticulo-striate arteries) MCA occlusion typically spare the striatum and primarily involve the neocortex. In addition these models do require craniectomy. In the model demonstrated in this article, a silicon coated filament is introduced into the common carotid artery and advanced along the internal carotid artery into the Circle of Willis, where it blocks the origin of the middle cerebral artery. In patients, occlusions of the middle cerebral artery are among the most common causes of ischaemic stroke. Since varying ischemic intervals can be chosen freely in this model depending on the time point of reperfusion, ischaemic lesions with varying degrees of severity can be produced. Reperfusion by removal of the occluding filament at least partially models the restoration of blood flow after spontaneous or therapeutic (tPA) lysis of a thromboembolic clot in humans.
In this video we will present the basic technique as well as the major pitfalls and confounders which may limit the predictive value of this model.

Filamentous occlusion of the Middle cerebral artery is a common model for studying ischemic stroke in mice.

Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are ...

Non-invasive Imaging of Acute Allograft Rejection after Rat Renal Transplantation Using 18F-FDG PET

The number of patients with end-stage renal disease, and the number of kidney allograft recipients continuously increases. Episodes of acute cellular allograft rejection (AR) are a negative prognostic factor for long-term allograft survival, and its timely diagnosis is crucial for allograft function 1. At present, AR can only be definitely diagnosed by core-needle biopsy, which, as an invasive method, bares significant risk of graft injury or even loss. Moreover, biopsies are not feasible in patients taking anticoagulant drugs and the limited sampling site of this technique may result in false negative results if the AR is focal or patchy. As a consequence, this gave rise to an ongoing search for new AR detection methods, which often has to be done in animals including the use of various transplantation models.
Since the early 60s rat renal transplantation is a well-established experimental method for the examination and analysis of AR 2. We herein present in addition small animal positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) to assess AR in an allogeneic uninephrectomized rat renal transplantation model and propose graft FDG-PET imaging as a new option for a non-invasive, specific and early diagnosis of AR also for the human situation 3. Further, this method can be applied for follow-up to improve monitoring of transplant rejection 4.

Non-invasive Imaging of Acute Allograft Rejection after Rat Renal Transplantation Using 18F-FDG PET

We herein present a rat renal transplantation model to non-invasively assess acute allograft rejection using positron emission tomography with 18F-fluorodeoxyglucose.

The number of patients with end-stage renal  disease, and the number of kidney allograft recipients continuously increases.  Episodes of acute cellular ...

Surgical Procedures for a Rat Model of Partial Orthotopic Liver Transplantation with Hepatic Arterial Reconstruction

Orthotopic liver transplantation (OLT) in rats using a whole or partial graft is an indispensable experimental model for transplantation research, such as studies on graft preservation and ischemia-reperfusion injury 1,2, immunological responses 3,4, hemodynamics 5,6, and small-for-size syndrome 7. The rat OLT is among the most difficult animal models in experimental surgery and demands advanced microsurgical skills that take a long time to learn. Consequently, the use of this model has been limited. Since the reliability and reproducibility of results are key components of the experiments in which such complex animal models are used, it is essential for surgeons who are involved in rat OLT to be trained in well-standardized and sophisticated procedures for this model.
While various techniques and modifications of OLT in rats have been reported 8 since the first model was described by Lee et al. 9 in 1973, the elimination of the hepatic arterial reconstruction 10 and the introduction of the cuff anastomosis technique by Kamada et al. 11 were a major advancement in this model, because they simplified the reconstruction procedures to a great degree. In the model by Kamada et al., the hepatic rearterialization was also eliminated. Since rats could survive without hepatic arterial flow after liver transplantation, there was considerable controversy over the value of hepatic arterialization. However, the physiological superiority of the arterialized model has been increasingly acknowledged, especially in terms of preserving the bile duct system 8,12 and the liver integrity 8,13,14.
In this article, we present detailed surgical procedures for a rat model of OLT with hepatic arterial reconstruction using a 50% partial graft after ex vivo liver resection. The reconstruction procedures for each vessel and the bile duct are performed by the following methods: a 7-0 polypropylene continuous suture for the supra- and infrahepatic vena cava; a cuff technique for the portal vein; and a stent technique for the hepatic artery and the bile duct.

Orthotopic liver transplantation in rats is an indispensable experimental model for biomedical research. Here we present our surgical procedures for orthotopic rat liver transplantation with hepatic arterial reconstruction using a 50% partial graft.

Orthotopic liver transplantation (OLT) in rats using a whole or partial graft is an indispensable experimental model for transplantation research, such as ...

Optimized System for Cerebral Perfusion Monitoring in the Rat Stroke Model of Intraluminal Middle Cerebral Artery Occlusion

The translational potential of pre-clinical stroke research depends on the accuracy of experimental modeling. Cerebral perfusion monitoring in animal models of acute ischemic stroke allows to confirm successful arterial occlusion and exclude subarachnoid hemorrhage. Cerebral perfusion monitoring can also be used to study intracranial collateral circulation, which is emerging as a powerful determinant of stroke outcome and a possible therapeutic target. Despite a recognized role of Laser Doppler perfusion monitoring as part of the current guidelines for experimental cerebral ischemia, a number of technical difficulties exist that limit its widespread use. One of the major issues is obtaining a secure and prolonged attachment of a deep-penetration Laser Doppler probe to the animal skull. In this video, we show our optimized system for cerebral perfusion monitoring during transient middle cerebral artery occlusion by intraluminal filament in the rat. We developed in-house a simple method to obtain a custom made holder for twin-fibre (deep-penetration) Laser Doppler probes, which allow multi-site monitoring if needed. A continuous and prolonged monitoring of cerebral perfusion could easily be obtained over the intact skull.

Cerebral perfusion monitoring has been demonstrated to improve accuracy in ischemic stroke models. Technical difficulties often limit the use of this essential tool for cerebrovascular research. In this video, an optimized system is shown to obtain a single or multi-site hemodynamic monitoring during intraluminal middle cerebral artery occlusion in rats.

The translational potential of pre-clinical stroke research depends on the accuracy of experimental modeling. Cerebral perfusion monitoring in animal ...

A Murine Model of Subarachnoid Hemorrhage

In this video publication a standardized mouse model of subarachnoid hemorrhage (SAH) is presented. Bleeding is induced by endovascular Circle of Willis perforation (CWp) and proven by intracranial pressure (ICP) monitoring. Thereby a homogenous blood distribution in subarachnoid spaces surrounding the arterial circulation and cerebellar fissures is achieved. Animal physiology is maintained by intubation, mechanical ventilation, and continuous on-line monitoring of various physiological and cardiovascular parameters: body temperature, systemic blood pressure, heart rate, and hemoglobin saturation. Thereby the cerebral perfusion pressure can be tightly monitored resulting in a less variable volume of extravasated blood. This allows a better standardization of endovascular filament perforation in mice and makes the whole model highly reproducible. Thus it is readily available for pharmacological and pathophysiological studies in wild type and genetically altered mice.

A standardized mouse model of subarachnoid hemorrhage by intraluminal Circle of Willis perforation is described. Vessel perforation and subarachnoid bleeding are monitored by intracranial pressure monitoring. In addition various vital parameters are recorded and controlled to maintain physiologic conditions.

In this video publication a standardized mouse model of subarachnoid  hemorrhage (SAH) is presented. Bleeding is induced by endovascular Circle of  Willis ...

The Rabbit Blood-shunt Model for the Study of Acute and Late Sequelae of Subarachnoid Hemorrhage: Technical Aspects

Early brain injury and delayed cerebral vasospasm both contribute to unfavorable outcomes after subarachnoid hemorrhage (SAH). Reproducible and controllable animal models that simulate both conditions are presently uncommon. Therefore, new models are needed in order to mimic human pathophysiological conditions resulting from SAH.
This report describes the technical nuances of a rabbit blood-shunt SAH model that enables control of intracerebral pressure (ICP). An extracorporeal shunt is placed between the arterial system and the subarachnoid space, which enables examiner-independent SAH in a closed cranium. Step-by-step procedural instructions and necessary equipment are described, as well as technical considerations to produce the model with minimal mortality and morbidity. Important details required for successful surgical creation of this robust, simple and consistent ICP-controlled SAH rabbit model are described.

The experimental intracranial pressure-controlled blood shunt subarachnoid hemorrhage (SAH) model in the rabbit combines the standard procedures &#8212; subclavian artery cannulation and transcutaneous cisterna magna puncture, which enables close mimicking of human pathophysiological conditions after SAH. We present step-by-step instructions and discuss key surgical points for successful experimental SAH creation.

Early brain injury and delayed cerebral vasospasm both contribute to unfavorable outcomes after subarachnoid hemorrhage (SAH). Reproducible and ...

Integrated Compensatory Responses in a Human Model of Hemorrhage

Hemorrhage is the leading cause of trauma-related deaths, partly because early diagnosis of the severity of blood loss is difficult. Assessment of hemorrhaging patients is difficult because current clinical tools provide measures of vital signs that remain stable during the early stages of bleeding due to compensatory mechanisms. Consequently, there is a need to understand and measure the total integration of mechanisms that compensate for reduced circulating blood volume and how they change during ongoing progressive hemorrhage. The body&#39;s reserve to compensate for reduced circulating blood volume is called the &#39;compensatory reserve&#39;. The compensatory reserve can be accurately evaluated with real-time measurements of changes in the features of the arterial waveform measured with the use of a high-powered computer. Lower Body Negative Pressure (LBNP) has been shown to simulate many of the physiological responses in humans associated with hemorrhage, and is used to study the compensatory response to hemorrhage. The purpose of this study is to demonstrate how compensatory reserve is assessed during progressive reductions in central blood volume with LBNP as a simulation of hemorrhage.

The purpose of this protocol is to demonstrate the techniques for measuring compensatory responses to reduced central blood volume using lower body negative pressure as a noninvasive experimental model of human hemorrhage which can be used to quantify the total integration of compensatory mechanisms to blood volume deficit in humans.

Hemorrhage is the leading cause of trauma-related deaths, partly because early diagnosis of the severity of blood loss is difficult. Assessment of ...

Transplantation of Adipose Tissue-Derived Stem Cell Sheet to Reduce Leakage After Partial Colectomy in A Rat Model

Anastomotic leakage is a disastrous complication after colorectal surgery. Although current methods for leakage prevention have different levels of clinical efficacy, they are until now imperfect solutions. Stem cell therapy using ASC sheets could provide a solution to this problem. ASCs are considered as promising candidates for promoting tissue healing because of their trophic and immunomodulatory properties. Here, we provide methods to produce high-density ASC sheets, that are transplanted onto a colorectal anastomosis in a rat model to reduce the leakage. ASCs formed cell sheets in thermo-responsive culture dishes that could be easily detached. On the day of the transplantation, a partial colectomy with a 5-suture colorectal anastomosis was performed. Animals were immediately transplanted with 1 ASC sheet per rat. ASC sheets adhered spontaneously to the anastomosis without any glue, suture, or any biomaterial. Animal groups were sacrificed 3 and 7 days postoperatively. Compared to transplanted animals, the incidence of anastomotic abscesses and leakage was higher in control animals. In our model, the transplantation of ASC sheets after colorectal anastomosis was successful and associated with a lower leakage rate.

The preparation and transplantation of adipose tissue derived stem cell (ASC) sheets onto insufficiently sutured colorectal anastomoses in a rat model is presented. This novel application shows that ASC sheets can reduce colorectal anastomosis leakage.

Anastomotic leakage is a disastrous complication after colorectal surgery. Although current methods for leakage prevention have different levels of ...

Implantation of hiPSC-derived Cardiac-muscle Patches after Myocardial Injury in a Guinea Pig Model

Due to the limited regeneration capacity of the heart in adult mammals, myocardial infarction results in an irreversible loss of cardiomyocytes. This loss of relevant amounts of heart muscle mass can lead to the heart failure. Besides heart transplantation, there is no curative treatment option for the end-stage heart failure. In times of organ donor shortage, organ independent treatment modalities are needed. Left-ventricular assist devices are a promising therapy option, however, especially as destination therapy, limited by its side-effects like stroke, infections and bleedings. In recent years, several cardiac repair strategies including stem cell injection, cardiac progenitors or myocardial tissue engineering have been investigated. Recent improvements in cell biology allow for the differentiation of large amounts of cardiomyocytes derived from human induced pluripotent stem cells (iPSC). One of the cardiac repair strategies currently under evaluation is to transplant artificial heart tissue. Engineered heart tissue (EHT) is a three-dimensional in vitro created cardiomyocyte network, with functional properties of native heart tissue. We have created EHT-patches from hiPSC derived cardiomyocytes. Here we present a protocol for the induction of left ventricular myocardial cryoinjury in a guinea pig, followed by implantation of hiPSC derived EHT on the left ventricular wall.

Here we present a protocol for the induction of left ventricular cryoinjury followed by the implantation of a cardiac muscle patch, derived from human iPS-cell cardiomyocytes in a guinea pig model.

Due to the limited regeneration capacity of the heart in adult mammals, myocardial infarction results in an irreversible loss of cardiomyocytes. This loss ...

Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry

When investigating the body&#39;s mechanisms for regulating cerebral blood flow, a relative measurement of microcirculatory blood flow can be obtained using laser Doppler flowmetry (LDF). This paper demonstrates a closed skull preparation that allows cerebral blood flow to be assessed without penetrating the skull or installing a chamber or cerebral window. To evaluate autoregulatory mechanisms, a model of controlled blood pressure reduction via graded hemorrhage can be utilized while simultaneously employing LDF. This enables the real time tracking of the relative changes in the blood flow in response to reductions in arterial blood pressure produced by the withdrawal of circulating blood volume. This paradigm is a valuable approach to study cerebral blood flow autoregulation during reductions in arterial blood pressure and, with minor modifications in the protocol, is also valuable as an experimental model of hemorrhagic shock. In addition to evaluating autoregulatory responses, LDF can be used to monitor the cortical blood flow when investigating metabolic, myogenic, endothelial, humoral, or neural mechanisms that regulate cerebral blood flow and the impact of various experimental interventions and pathological conditions on cerebral blood flow.

This article demonstrates the use of laser Doppler flowmetry to evaluate the ability of the cerebral circulation to autoregulate its blood flow during reductions in arterial blood pressure.

When investigating the body&#39;s mechanisms for regulating cerebral blood flow, a relative measurement of microcirculatory blood flow can be obtained ...