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Background: Organ function after liver transplantation is determined by ischemia-reperfusion injury. Destruction of Kupffer cells with gadolinium chloride (GdCl3) has been shown to have a possible preventive effect on the extent of this injury, which can be extrapolated by analyzing the distribution of hepatic microperfusion. The aim of this study was to evaluate the protective effect of GdCl3 on disturbances of microperfusion in the transplanted liver., Methods: Landrace pigs were randomly divided into three groups. In the control group (CG; n=6) a mapping of the native liver was conducted. For mapping, the four hepatic liver lobes were named from right to left with A to D and every lobe was divided into three vertical segments (cranial, medial, and caudal). In each of these 12 areas, microperfusion was quantified using a thermodiffusion probe (TD [mL/100 g/min]). The other two groups were considered as transplanted treated group (TTG; n=10) and transplanted nontreated group (TnTG; n=10). The TTG received an infusion of 20 mg/kg GdCl3 intravenously 24 hours before organ harvesting. Then standardized orthotopic liver transplantation was performed. In TnTG, standardized orthotopic liver transplantation was carried out without prior GdCl3 injection. In the recipients, the microperfusion of transplanted livers were mapped in both TnTG and TTG, in two different time points (1 hour [n=5] and 24 hours (n=5]) after reperfusion., Results: A significant reduction of macrophages in the TTG livers in comparison to the CG and TnTG livers was observed (P<.05). However, the number of macrophages in CG and TnTG livers showed no significant difference (P>.05). Regarding liver microperfusion, in TnTG, a marked heterogeneity was detected in the livers after reperfusion. Significant differences between liver lobes (horizontal planes; P=.032) and vertical layers of intralobar liver parenchyma (P=.029) were observed. The same pattern was seen in TTG livers after reperfusion and a significant difference between horizontal (P=.024) and vertical layers (P=.018) of liver tissue were observed. Comparing intralobar regional flow data between vertical planes 24 hours after reperfusion still showed a prominent variation of hepatic tissue perfusion in TnTG livers (P=.028). Within the same horizontal layers, no significant differences between lobes were measured anymore (P=.16). Contrary to TnTG, in TTG, a homogenous pattern of regional liver tissue perfusion was recorded 24 hours after reperfusion. Comparison of TD data on the liver regions showed no significant microperfusion differences in either horizontal (P=.888) or vertical (P=.841) layers., Conclusions: Application of GdCl3 resulted in a significant reduction of Kupffer cells. Twenty four hours after transplantation microperfusion showed a homogeneous pattern, which constituted an earlier and better recovery of the transplanted liver. Therefore, destruction of Kupffer cells reduced ischemia-reperfusion injury and seemed to be responsible for the early recovery of microperfusion disturbances and thus for an improvement of graft function.

Background: Pulmonary reperfusion injury is a significant risk factor following lung transplantation (LTx). Unfortunately, in vivo observations and quantitative analyses of the pulmonary microcirculation following LTx are technically demanding., Methods: Pigs, weighing 18 to 22 kg, served as the laboratory animals. The left lung was harvested and preserved using donor aortic vessel segments, the pulmonary artery, and the cuff of the lung veins were extended. After 4 hours of ischemia, the lungs were transplanted by direct connection of the conduits to the left atrial appendage and the left pulmonary artery of the recipient. The lungs were placed extrathoracically and ventilated. The recipient left lung was excluded. With this procedure, mechanical trauma to the lung and moving artefacts were avoided. Intravital microscopic observation became feasible., Results: Following reperfusion, oxygenation of pulmonary venous blood was excellent. However, blood flow distribution was significantly reduced to the transplanted lung compared with the native right recipient lung. Pulmonary vascular resistance was significantly increased, dropping from 3500 to 1000 dynes x s x cm(-5) during reperfusion compared to a value of 500 for the native right lung. The pulmonary microcirculation showed a significant number of no-reflow areas with extremely reduced red blood cell velocities. Greater than 90% of microvessels (<30 microm) showed velocities below 0.1 mm/sec. In conclusion, microvascular injury seems to be a major pathogenic factor for the development reperfusion failure. Quantification of alterations within the microvasculature may shed light on various treatment modalities that reduce perfusion failure.

The cause of transplant failure may be difficult to define. However, organ retrieval before preservation and transplantation is an important factor. Organ manipulation during harvesting, which is inevitable with most techniques, leads to injury upon reperfusion including microcirculatory disturbances. Recently, laparoscopic organ retrieval has been successfully performed for human living donor liver transplantation (LDLT). Pneumoperitoneum for laparoscopy changes the pattern of hepatic blood flow. To study the effects of pneumoperitoneum on the graft prior to cold storage, livers from Sprague-Dawley rats underwent pneumoperitoneum with an intra-abdominal pressure of 8 mm Hg for 90 minutes. Subsequently, intravital microscopy was performed to assess intrahepatic microcirculation and transaminases were measured. Serum transaminases increased 1.5-fold compared with sham controls (P < .05). Intrahepatic microcirculation was significantly disturbed immediately after pneumoperitoneum. If this is confirmed in humans, laparoscopic organ retrieval for LDLT would be expected to decrease graft quality and not be beneficial in liver transplantation.

Orthotopic liver transplantation (OLT) in rat is a demanding procedure, which has become a popular model to investigate various problems. Our aim was to review and analyze the various techniques of experimental OLT in the rat. A review of the literature revealed 30 techniques or technical modifications. Each modification represented a change or a simplification of the reconstruction method of five anatomical structures, which are cornerstones of a successful OLT: the suprahepatic inferior vena cava (SHVC), portal vein (PV), infrahepatic inferior vena cava (IHVC), hepatic artery (HA), and bile duct (BD). SHVC is anastomosed via microsuture or cuff. The PV anastomosis is performed by microsuture, cuff, or a microsuture-temporary splint technique. IHVC is reconstructed by a microsuture, cuff, or microsuture-temporary splint technique. Arterialization has been accomplished via microsuture (aortic segment, celiac segment, or aortic patch), cuff, splint, sleeve, or telescopic method. Nonarterialization of the graft has also been described. Methods for BD reconstruction include pull-through, telescopic, splint, and T-tube. Although a high level of microsurgical skill is the basic requirement in the microsuture technique which provides the most physiological situation and concomitantly reduces thrombosis, it increases anhepatic time compared to the cuff procedure. The learning curve of microsuture techniques is flat; beginners need much practice to become expert. The most physiologic techniques for anastomoses are preferred for long-term survival studies, while the faster techniques are options for short-term survival studies. Each research group must choose techniques according to study defined aims.