Technique of successful lung transplantation in humans

We have performed five single lung transplantations for end-stage pulmonary fibrosis, with four long-term survivors. Two patients underwent right lung transplantation and two underwent left lung transplantation. The procedure is performed with one lung anesthesia, although cardiopulmonary bypass is available on standby if required. Donor and recipient procedures are performed in adjacent operating rooms. On the basis of laboratory studies, a pedicle of omentum is wrapped around the bronchial anastomosis after its completion to restore bronchial artery circulation and protect the anastomosis. The four patients were discharge from the hospital within 4 to 6 weeks and three returned to normal employment at 3 months. Success in these cases is attributed to careful patient selection, use of cyclosporine, and use of an omental pedicle to protect and improve healing of the bronchial anastomosis.     

Low-dose carbon monoxide inhalation prevents ischemia/reperfusion injury of transplanted rat lung grafts

BACKGROUND: Carbon monoxide (CO), a byproduct of heme catalysis by heme oxygenases, has been shown to provide protection against ischemia/reperfusion (I/R) injury. We examined the cytoprotective effect of CO at a low concentration on cold I/R injury of transplanted lung grafts. METHODS: Orthotopic left lung transplantation was performed in syngenic Lewis to Lewis rat combination. Grafts were preserved in University of Wisconsin solution at 4 degrees C for 6 hours. Donors and/or recipients were exposed to CO (250 ppm) in air for 1 hour before surgery and then continuously post-transplantation. RESULTS: Blood oxygen partial pressure of graft pulmonary veins in the CO-treated group versus the air-treated group was significantly higher. The increase of messenger RNA of inflammatory mediators such as interleukin-6, tumor necrosis factor-alpha, inducible nitric oxide synthase, and cycloooxygenase-2 was markedly inhibited in the CO-treated group. The expression of phosphorylated-extracellular signal-regulated protein kinase 1/2 was significantly reduced in the CO-treated group. CO treatment reduced the number of infiltrating macrophages into the lung grafts. Vascular endothelial cells detected by CD31 stain were well preserved in CO-treated grafts, while those in air-treated grafts were faint and interrupted. CONCLUSIONS: These results demonstrate that exogenous low-dose CO treatment of donors and recipients can prevent lung I/R injury and significantly improve function of lung grafts after extended cold preservation and transplantation.     

Airway pathology in the transplanted rat lung

Bronchiolitis obliterans has emerged as the most significant long-term complication of human heart-lung transplantation. Possible causes include rejection, infection, altered bronchial circulation, and denervation. We attempted to assess the role of some of these possibilities by reviewing the airway histology in nonimmunosuppressed orthotopic rat left lung allografts in three strain combinations: BN-to-LEW (major histocompatibility complex [MHC]-incompatible) n = 27; (LEW X BN)F1-to-LEW, n = 11; and F344-to-LEW (minor loci-incompatible) n = 18. Fifteen syngeneic transplants (LEW-to-LEW) served as controls. After assigning the lungs to a rejection phase (latent, vascular, alveolar, or destructive), the airway pathology was specifically examined. In the latent phase, only changes attributable to transplantation per se were identified. In the vascular phase in the BN-to-LEW rats and (LEW X BN)F1-to-LEW rats, the bronchioles were surrounded by dense cuffs of activated lymphocytes. The lymphocytic infiltrate then progressively involved the lamina propria and epithelium, where it became associated with focal epithelial cell necrosis. Eventually the epithelium became ulcerated (alveolar phase), and the submucosa and luminal surface became replaced by granulation tissue, which frequently protruded into the lumen in a bronchiolitis obliterans pattern. In the destructive phase the changes were similar to those in the alveolar phase, but were more severe. In the F344-to-LEW rats the airway changes were less prominent, although the remainder of the lungs was at comparable phases of rejection. These changes were not observed in the right (nontransplanted) lungs or the control (LEW-to-LEW) lungs. The findings in these animals suggest that the process of rejection affects the airways and may result in posttransplantation bronchiolitis obliterans.     

移植肝再灌注损伤的发生机制

目的：介绍有关移植肝再灌注损伤发生机制的研究动向,方法：复习有关文献并进行综述性报告。结果：移植肝冷保存后的再灌注损伤的发生机制主要有：（1）内皮细胞损伤和Kupffer细胞激活,导致一系列细胞因子的产生,引起移植肝损伤,并引发全身炎症反应综合征。（2）白细胞,血小板与肝血窦壁的粘附而损害肝细胞,并可阻塞肝血窦造成“无复流”现象;（3）pH值的变化,再灌注后移植肝的代谢恢复正常后,组织内pH值的改变可引起肝细胞损伤,并可造成线粒体的肿胀,使肝细胞的功能降低,（4）复氧损伤,主要与白细胞释放活性氧（ROS）有关,结论：移植肝再灌注损伤是多种因素综合作用的结果,在再灌注前后提高肝细胞和内皮细胞的活性,抑制Kupffer细胞的激活,减少ROS及肿瘤坏死因子（TNF）的产生将是今后预防移植肝再灌注损伤研究的关键。     

Leukocyte-depleted reperfusion of transplanted human hearts prevents ultrastructural evidence of reperfusion injury.

The present study examines whether leukocyte depletion can prevent postreperfusion ultrastructural injury in transplanted human hearts. Thirty-two patients undergoing orthotopic cardiac transplantation were randomized to receive either enriched, warm, whole blood (Group I; n = 16) or enriched, warm, leukocyte-depleted blood (Group II; n = 16) reperfusion. Donor hearts were arrested with 1 liter of 4 degrees C crystalloid cardioplegia and topically cooled. RV endomyocardial biopsies taken at end-ischemia and following reperfusion were assessed in a blinded fashion and graded according to injury (1 = minimal to 4 = severe). The mean ischemic time (Group I = 142 min, Group II = 153 min) was similar in the two groups. End-ischemic biopsies showed mild-moderate interstitial edema and mild capillary endothelial swelling in both groups with similar injury scores (Group 1 = 1.3 +/- 0.09 (means +/- SEM), Group 2 = 1.25 +/- 0.08). Postreperfusion biopsies in Group I showed nuclear chromatin clumping, moderate mitochondrial swelling, marked capillary endothelial swelling, and marked interstitial edema with a grade of 2.6 +/- 0.14 (P less than 0.001, paired t test). In contrast, postreperfusion biopsies in Group II showed minimal changes with a grade of 1.33 +/- 0.09, P less than 0.0001 in comparison to Group I Leukocyte-depleted reperfusion of human transplanted hearts prevents ultrastructural injury. This may allow safe extension of the ischemic period and result in improved graft function.     

Myocardial neutrophil sequestration during reperfusion of the transplanted rabbit heart.

BACKGROUND: Neutrophils are major participants in myocardial reperfusion injury, but the relationship between ischemic time and the extent of the neutrophil sequestration in heart transplantation has not yet been systematically studied. This study was designed to determine whether increased ischemic time would cause greater neutrophil sequestration during reperfusion of the globally ischemic heart. METHODS: Rabbit hearts were arrested with cardioplegia, explanted, and subjected to either 1 or 4 hours of global ischemia at 4 degrees C before being heterotopically transplanted into a recipient rabbit's abdomen for reperfusion. Each heart was reperfused for either 4, 8, or 12 hours. Between 3 and 7 hearts were studied (average = 5.8) for each combination of ischemic and reperfusion time (total = 35). A myeloperoxidase (MPO) assay was used to qualify neutrophil content. RESULTS: MPO activity (U/g wet weight) was not significantly different at 4, 8, and 12 hours of reperfusion (0.33 +/- 0.05, 0.20 +/- 0.04, 0.26 +/- 0.04: p = 0.13), but was significantly increased at 4 hours compared to 1 hour ischemia (0.34 +/- 0.04 vs 0.19 +/- 0.03: p = 0. 006). Interaction between ischemic and reperfusion times was not significant (p = 0.12). MPO activity was below the measurable threshold in 5 freshly excised control hearts. CONCLUSIONS: These results suggest that acute reperfusion injury will be more severe in the hearts subjected to 4 hours ischemia and indicate the need to consider neutrophil-mediated reperfusion injury when addressing cardioprotective interventions for cardiac preservation and reperfusion after transplantation. Neutrophil-mediated reperfusion injury of the rabbit myocardium after heterotopical transplantation is more severe in hearts subjected to 4 hours of ischemia vs 1 hour of ischemia prior to transplantation.     

Myocardial preservation: controlled reperfusion

Reperfusion injury after reestablishing coronary flow by releasing the aortic cross clamp after cardiac surgery with cardioplegic arrest causes myocardial damage and even death. Attenuation of this reperfusion response by controlling the biochemical and physical environment can avoid morbidity and mortality. Use of a warm reperfusate with addition of drugs that are known to decrease reperfusion injury with manipulation of coronary vascular resistance and the physical parameters of the reperfusion environment helps the heart to reestablish coronary perfusion while decreasing the harm produced by the period of ischemia that occurs during cardiac surgery with intermittent cardioplegic arrest.     

Inhaled nitric oxide attenuates reperfusion inflammatory responses in humans

BACKGROUND: Reduced bioavailability of endothelium-derived nitric oxide associated with reperfusion could potentially exacerbate the inflammatory response during reperfusion. Evidence suggests the pharmacologic effects of inhaled nitric oxide may extend beyond the pulmonary vasculature, and this is attributed to nitric oxide-derived complexes in blood that ultimately orchestrate antiinflammatory effects. In this study, the authors evaluated the potential for inhaled nitric oxide (80 ppm) to attenuate inflammation instigated by ischemia-reperfusion in a human model using patients undergoing knee surgery where a tourniquet was used to produce a bloodless surgical field. METHODS: Inhaled nitric oxide (80 ppm) was administered before tourniquet application and continued throughout reperfusion until the completion of surgery. Venous blood samples were collected before and after reperfusion, for the measurements of nitrate and nitrite, CD11b/CD18, soluble P-selectin, and lipid hydroperoxide. Muscle biopsies were obtained from the quadriceps muscle before skin closure and analyzed for myeloperoxide, conjugated dienes, and nuclear factor-kappaB translocation. RESULTS: Administration of inhaled nitric oxide (80 ppm) significantly attenuated the inflammatory response characterized by reduced expression of CD11b/CD18, P-selectin, and nuclear factor kappaB compared with the control group. This was accompanied by increased plasma levels of nitrate and nitrite and reduced oxidative stress. CONCLUSIONS: Administration of inhaled nitric oxide at 80 ppm significantly reduces inflammation in lower extremity ischemia-reperfusion in humans. This observation supports the concept that during diseases characterized by dysfunction in nitric oxide metabolism, inhaled nitric oxide may be an effective therapy to replenish systemic nitric oxide, thus retarding inflammatory-mediated injury.     

治疗性高碳酸血症对大鼠移植肺细胞凋亡的影响

目的探讨治疗性高碳酸血症对移植肺细胞凋亡的影响及其可能的机制。方法26只Wistar大鼠,供体鼠和受体鼠各13只,肺移植成功后随机分为2组：对照组（n=6）和治疗组（n= 7）。对照组再灌注期间吸入50%N2-50%O2混合气体;治疗组再灌注期间吸入40%N2-60%O2- 100%CO2混合气体,调节吸入二氧化碳和氧气的流量,维持吸入氧浓度50%,动脉血二氧化碳分压（PaCO2）80～100 mm Hg。记录受体鼠机械通气15 min时平均动脉压（MAP）、PaCO2和动脉血氧分压（PaO2）作为基础值,再灌注期间每15分钟记录1次,直至实验结束。再灌注90 min时放血处死大鼠,采用考马斯亮蓝法测定支气管肺泡灌洗液（BALF）蛋白浓度;取左肺组织,计算湿/干重比;采用免疫组化法测定Bax、Bcl-2的表达;采用TUNEL法检测细胞凋亡情况。结果与基础值比较,再灌注期间对照组MAP和PaO2降低（P〈0.05）;与对照组比较,再灌注期间治疗组MAP、PaCO2和PaO2升高,BALF蛋白浓度、肺组织W/D、Bax表达和细胞凋亡指数降低（P〈0.05）,Bcl-2表达差异无统计学意义（P〉0.05）。结论治疗性高碳酸血症可抑制大鼠移植肺细胞凋亡,其机制与下调Bax蛋白表达有关。     

The use of allopurinol in the inhibition of obliterative bronchiolitis of the transplanted lung

Long-term survival following lung transplantation has been limited primarily by the development in patients' lungs of a rejection-related obliteration of terminal bronchioles by fibroblasts. It is known to result from frequent and persistent acute lung rejection and its physiological features include a progressive decline in the lung function measurement of forced expiratory volume in 1 s. We report the dramatic effect on this hitherto usually fatal condition of a specific inhibition of purine metabolism at the xanthine oxidase enzyme by the hypoxanthine analogue allopurinol. The effect of this drug in heart-lung transplant patients with deteriorating lung function in reducing the rate of rejection and in stabilizing lung function was apparent over as short a follow-up period as 3 months and in ten patients. Although the follow-up time is short, we believe the effects are so striking as to require reporting although the mechanisms of this phenomenon are not yet well understood.     

Prevention of ischemic damage using controlled limb reperfusion

Following prolonged limb ischemia, a reperfusion injury may occur with the reintroduction of unmodified blood, resulting in tissue loss and, in severe cases, limb loss. We have shown that the reperfusion injury in the heart can be minimized by using controlled reperfusion with a substrate-enriched cardioplegia solution prior to restoring normal blood flow. This article describes two clinical cases in which we used controlled reperfusion in an ischemic limb to prevent limb loss. It demonstrates that a controlled, substrate-enhanced, hypocalcemic, leukodepleted, modified blood reperfusate solution can minimize limb reperfusion damage and improve functional recovery. This preliminary experience is presented to familiarize surgeons with this form of treatment and to describe the solutions and method of administration that can be used to avoid the devastating complications of severe limb ischemia.