Significance of bronchial mucosal blood flow for the monitoring of acute rejection in lung transplantation.

Bronchial mucosal blood flow (BMBF) was measured with a laser-Doppler flowmeter in a canine model (n = 20), and the measurement was evaluated to see if it was a useful method for diagnosing allografted lung rejection. The ratio of the value of BMBF at the level of the donor second carina against that at the level of carina (the L/C ratio, an index of BMBF of donor bronchus) decreased in accordance with the extent of lung rejection, and it increased and entered the normal range with the reversal of lung rejection. Compared with the L/C ratio and the rejection grade by histologic changes in open-lung biopsy, the L/C ratio at grade 0 (latent phase) was 0.91 +/- 0.07; at grade Ia (early vascular phase), 0.86 +/- 0.05; at grade Ib (late vascular phase), 0.68 +/- 0.10; at grade II (early alveolar phase), 0.60 +/- 0.14; and at grade III (late alveolar phase), 0.50 +/- 0.15. A significant difference was noted between grades Ia and Ib (p less than 0.01) and between grades Ib and III (p less than 0.01). The sensitivity and the specificity in the detection of early rejection before grade Ib were 96% and 92%, with only one false-negative and two false-positives resulting from 51 measurements of BMBF. In three cases of serious lung infections, the L/C ratio did not fall, and the rejection could be distinguished from infection. These results suggest that measurement of the BMBF is useful for detecting the early rejection of transplanted lungs.     

Value of mucosal biopsies in the monitoring of acute small bowel rejection

The value of mucosal biopsies in evaluating small bowel rejection is controversial. In this study, the value of mucosal biopsies was estimated in unmodified porcine small bowel rejection. Ten animals received the distal half of the small bowel as a heterotopic loop (Thiry-Vella loop). The allografts were followed by proximally and distally harvested full-thickness and mucosal biopsies every other day, starting from the 3rd day and continuing until the grafts became necrotic. The histological parameters in both types of biopsies were semiquantitatively scored from 0 to 3 and compared with each other. The difference in mean values on subsequent days was not remarkable, the results favoring slightly higher values in full-thickness than in mucosal biopsies. Our results suggest that multiple mucosal biopsies are adequate in monitoring morphological changes of small bowel grafts during rejection and that the proximal and distal ileum are similarly affected by acute rejection. Received: 17 June 1996 Received after revision: 20 November 1996 Accepted: 6 December 1996     

肾移植术后急性体液性排斥反应的监测及其临床意义

目的 探讨肾移植后发生急性体液性排斥反应(AHR)的可能机制,及其在临床早期诊断和防治AHR中的重要意义.方法 回顾分析2006年1月至2010年12月间296例肾移植受者的临床资料.肾移植术后,采用酶联免疫吸附试验(ELISA)动态监测受者群体反应性抗体(PRA)和供者特异性抗体(DSA)水平,采用免疫组织化学法和HE染色检查移植肾组织的病理形态学改变及C4d的沉积、浸润淋巴细胞表面分子标记.AHR诊断标准参照Banff 2005标准,并结合受者的临床相关指标.结果 296例受者中,术后共有25例发生了AHR,发生率为8.4％ (25/296).术前PRA阳性者和阴性者术后AHR的发生率分别为23.1％(6/26)和7.0％(19/270),两者比较,差异有统计学意义(P＜0.01).术后发生AHR和未发生AHR受者的DSA阳性率分别为88.0％(22/25)和0.4％(1/271),出现C4d沉积阳性率分别为80.0％(20/25)和6.7％ (4/60),两者间DSA阳性率和C4d沉积阳性率的比较,差异均有统计学意义(P＜0.01).通过调整免疫抑制方案和(或)应用静脉注射免疫球蛋白、血浆置换、抗胸腺细胞球蛋白及利妥昔单抗等治疗后,19例AHR被逆转,其余6例因治疗无效,发生移植肾破裂,导致移植肾被切除.结论 PRA和DSA在肾移植术后AHR的发生中起重要作用,术后应立即开始监测PRA和DSA,以达到预防、早期诊断和合理治疗AHR的目的,进而改善移植肾的存活.     

Endoscopic measurements of gastric mucosal blood flow in dogs

The feasibility and validity of endoscopic measurements of gastric mucosal blood flow (GMBF) using 3% H2 gas clearance were investigated in the intact stomach of anesthetized dogs. Platinum electrodes were lengthened and modified to permit passage through the instrument channel of a standard gastroscope. In five anesthetized dogs, antral mucosal blood flow (103.2 +/- 5.3 ml/min/100 g tissue) was significantly higher (P less than 0.05) than that in the corpus (66.9 +/- 7.1 ml/min/100 g tissue). Histamine stimulation selectively increased flow in the corpus to 134.5 +/- 7.5 ml/min/100 g tissue. Comparison of endoscopic GMBF measurements in these five dogs on 2 different days revealed a close correlation (r = 0.87, P less than 0.001). Endoscopic H2 clearance measurements obtained in five awake dogs were not significantly different from those obtained during pentobarbitol anesthesia. In 12 dogs, GMBF determined by endoscopic H2 gas clearance showed a good agreement (r = 0.91, P less than 0.001) with that measured by radioactive microspheres. These two methods also demonstrated comparable changes in GMBF induced by intravenous infusion of histamine and vasopressin. It was concluded that 3% H2 gas clearance can be used to accurately and reproducibly measure GMBF through the endoscope, a unique advantage of this method for potential clinical use.     

Histologic changes in donor bronchi may explain the reduced mucosal blood flow seen during acute lung allograft rejection.

We assessed the histologic changes in donor and recipient bronchi from 15 dogs that had received a lung transplant and related these changes to the severity of acute rejection seen in the parenchyma of these same lungs. Minimal rejection was associated with no abnormal change in either the donor or the recipient bronchi. In mild lung rejection, mononuclear cell cuffings were seen around bronchial arteries in donor bronchial adventitia, although few mononuclear cell infiltrates were seen in the submucosa. Moderate lung rejection was associated with more prominent mononuclear cell cuffings in the donor bronchial adventitia and mucosal infiltrates of mononuclear cells in the membranous portion. In cases of severe lung rejection, the mononuclear cell infiltrates were also apparent in the cartilaginous portion of the donor bronchial mucosa. Moreover, submucosal edema and detachment of bronchial epithelium were seen. These histologic changes were not observed in the recipient bronchi during acute rejection, nor were they seen in the donor and the recipient bronchi during lung infection without rejection. They might, therefore, reflect acute rejection in the donor bronchus. These results might provide the histologic support for our previous observation of decreased bronchial mucosal blood flow measured by the laser Doppler flowmeter in relation with the extent of acute lung rejection.     

应用彩色超声波监测移植肾血流变化的临床价值

通过对５１８例肾移植患者连续７６１次彩色超声波结果进行了回顾性分析，从６项超声指标中，比较了功能正常的移植肾与排斥，急性肾小管坏死，肾积水和环孢素肾毒性血液动力学变化。并提出了肾移植排斥时除阻力指数升高与舒张末期最小速度／血管内径，血流收缩期最大速度比值下降外，移植肾血流速度减慢，血流量减低。     

The effect of pulmonary arterial flow and positive end-expiratory pressure on retrograde bronchial mucosal blood flow.

Bronchial viability within the first few days after lung transplantation depends on collateral blood flow from the pulmonary to the bronchial circulation. In the present study the relationship between pulmonary arterial flow and retrograde bronchial blood flow, and the effect of positive end-expiratory pressure on bronchial blood flow were evaluated by laser Doppler velocimetry in an isolated in situ lung perfusion model. Nine adult mongrel dogs were exsanguinated by way of a left atrial cannula. Blood was pumped by a roller pump into the main pulmonary artery. Lungs were perfused at random flow (in 0.5 L/min increments) at rates of 1 to 3 L/min. Steady-state laser Doppler velocimetric measurements at each level of flow were made at the tracheal carina and both bronchial carina. Pump flow was then set at baseline cardiac output and positive end-expiratory pressure was applied. Steady-state laser Doppler velocimetric measurements were obtained at each level of positive end-expiratory pressure (5 cm H2O and 10 cm H2O). Bronchial blood flow correlated well with pulmonary arterial flow (for the tracheal carina; rs = 0.912 and p less than 0.0005; for the right bronchial carina, rs = 0.799, p less than 0.0005; for the left bronchial carina, rs = 0.917, p less than 0.0005; where rs is the common correlation coefficient). The bronchial blood flow at the left bronchial carina and the right bronchial carina were significantly higher than at the tracheal carina (p less than 0.005 and p less than 0.05, respectively). At baseline cardiac output, bronchial blood flow in the in situ model was approximately 50% lower than observed in the intact animals. Positive end-expiratory pressure increased the bronchial blood flow at the tracheal carina and both bronchial carina (p less than 0.05).     

持续氧合血灌注供心对移植心脏急性排斥反应的影响

目的 观察持续氧合血灌注供心对移植心脏急性排斥反应的影响.方法 建立无缺血再灌注损伤(同系A1组、异系B1组)和缺血再灌注损伤(同系A2组、异系B2组)4种异位心脏移植模型,并设立对照组C,术后第7天取标本,Real-Time聚合酶链反应(PCR)检测移植心脏MHC-Ⅱ、B7-2 mRNA表达,免疫组织化学法检测CD4+T细胞浸润.结果 A2、A1组MHC-ⅡmRNA分别为9.30±0.53、1.48 ±0.31 (P ＜0.05)、B7-2 mRNA分别为5.45±0.43、1.46 ±0.30(P ＜0.05)、CD4+T 细胞数分别为4.86±0.90、3.14 ±0.69(P＜0.05);B2、B1组MHC-ⅡmRNA分别为21.12±1.15、14.14±0.80(P ＜0.05)、B7-2 mRNA分别为13.41±0.43、8.23±0.48(P ＜0.05)、CD4+T细胞数分别为43.57±2.07、18.86±0.69(P ＜0.05).结论 持续氧合血灌注供心有助于减轻或延缓急性排斥反应的发生.     

Airway epithelium of transplanted lungs with and without direct bronchial artery revascularization.

OBJECTIVE: Normal systemic blood flow to the airways and lung parenchyma of transplanted lungs can only be re-established by direct bronchial artery revascularization. The purpose of the present study was to investigate whether such direct bronchial artery revascularization would preserve ciliary function, previously shown to be reduced in lungs transplanted without revascularization. METHODS: Twenty-five single lung transplanted patients were included in this study. Complete direct bronchial artery revascularization was achieved in eight patients. In 16 patients the procedure had either failed (n = 10) or was not attempted (n = 6). In one patient the result of the revascularization was unknown. Airway epithelium samples were obtained from the native and the transplanted lungs during bronchoscopic examinations. Airway erythema and excessive secretion were registered. The epithelium samples underwent histological examination and ciliary beat frequency was measured in vitro by video recording. Transbronchial biopsies from the transplanted lungs were examined for signs of rejection and bronchitis. RESULTS: No differences in ciliary beat frequency nor in the distribution of ciliated/de-ciliated columnar epithelium cells between native lungs and transplanted lungs with or without successful direct bronchial artery revascularization could be demonstrated. In 38% of the transplanted lungs without successful revascularization metaplastic or squamous epithelium was present, while lungs with successful revascularization had only normal columnar epithelium. Ongoing rejection or airway erythema did not influence ciliary beat frequency. Excessive secretion in the airways was the only finding associated with significantly increased ciliary beat frequency. CONCLUSIONS: Ciliary beat frequency of epithelium cells of transplanted lungs did not differ from that of native lungs and consequently direct bronchial artery revascularization did not have any demonstrable important influence. Excessive secretion in the airways was associated with increased ciliary beat frequency. The histological findings also showed that the abundance of ciliated cells was preserved in transplanted bronchi irrespective of bronchial artery revascularization. However, epithelium metaplasia was only seen in transplanted bronchi without revascularization.     

Plasmapheresis in the treatment of the acute reaction of transplanted kidney rejection

A total of 14 patients with acute rejection of transplanted kidney were treated with plasmapheresis (in combination with prednisolone supporting therapy in a dose of 15 mg/kg). For the arrest of the rejection it was necessary to use 4 sessions of plasmapheresis on average for each person (from 3 to 8 sessions). The average volume of discharged plasma, 2,000 ml approximately, was compensated with frozen plasma. Plasmapheresis was exercised by plasma separation with an "Asahi" plasma filter with the surface of 0.5 m2. Plasmapheresis successfully arrested the rejection in 50 per cent of the patients. Pathogenetic reasonability of plasmapheresis for the treatment of the aforementioned patients (elimination of toxins, circulating immune complexes, elevation of C3 and C4 components of the complement) was substantiated. In patients who had undergone plasmapheresis for the arrest of acute rejection, lowered levels of proteinuria were considered as a favourable prognostic sign.     

Significance of donor-specific antibodies in acute rejection

Significant advances in recent years in the diagnosis of antibody-mediated graft rejection have led to the re-evaluation of humoral alloreactivity in organ transplantation. By introducing the "C4d-test" into the work-up of transplant biopsies, donor-specific antibodies were claimed to be directly involved in about 30% of acute rejection episodes. The diagnostic criteria for antibody-mediated rejections of renal grafts are now incorporated in the "Banff classification" as refined at a recent consensus conference. Capillary C4d is not always concordant with circulating anti-HLA-antibodies, even if these are assayed with improved techniques. Antibody absorption within the graft and antigens other than HLA, therefore, have to be considered. Effective therapy of humoral rejection is now available. Serial assessment of humoral alloreactivity also in the posttransplantation period is now mandatory to identify at-risk patients.     

Intramyocardial impedance measurements for diagnosis of acute cardiac allograft rejection

BACKGROUND: Measurements of intramyocardial impedance at high frequencies can indicate alterations in cell membranes and intracellular spaces during acute cardiac allograft rejection. METHODS: Fifteen beagle dogs underwent heterotopic heart transplantation and were immunosuppressed with cyclosporine and methyl prednisolone (MP). Impedance was determined twice daily by means of four screw-in electrodes in the right and left ventricle. Transmyocardial biopsies and the intramyocardial electrogram (IMEG) were performed as reference methods. A total of 23 rejection episodes were induced. When acute rejection was recognized histologically and through IMEG readings, the animals were treated with a bolus of 125 mg of methyl prednisolone over 5 consecutive days. Treatment of rejection was controlled by biopsy and IMEG. RESULTS: All hearts showed a uniform decrease in impedance of about 28.3%+/-5.5% immediately after transplantation, which subsequently reached a stable plateau after 7 to 8 days. Impedance values then remained unchanged as long as rejection was absent. Biopsy findings of grades 1A to 1B (ISHLT) were accompanied by a statistically significant increase in impedance of 12.2%+/-2.5%; of grades 2 to 3A of 19.2%+/-3.2% and of grades 3B to 4 of 27.0%+/-2.9%. Sensitivity was 96%, specificity 91%. Successful treatment of rejection led to a decrease of impedance to the initial levels. CONCLUSIONS: The amount of increase in impedance of high frequencies is a method to stratify acute cardiac allograft rejection into grades like histologically grading. The effectiveness of rejection treatment can also be monitored through impedance measurement. The method is also applicable for telemetric rejection monitoring by means of an implantable device.     

Lessons learned with noninvasive cardiac monitoring for acute rejection

INTRODUCTION: Computerized Heart Allograft Rejection Monitoring (CHARM), used for noninvasive rejection monitoring in heart transplant recipients, is based on the analysis of ventricular evoked response (VER) signals. This study evaluated the prognostic validity of the TslewC, a parameter extrapolated from the VER. METHODS: During orthotopic heart transplantation (OHT) 2 unipolar, fractally coated, screw-in leads implanted epimyocardially were connected to a telemetric pacemaker. Recordings of IEGMs were performed routinely at hospital and at outpatient visits. Data processing yielded trend curves. TslewC was calculated from the tangent of VER. One hundred five patients divided into survivors and nonsurvivors, were compared using a two-tailed Student's t test. RESULTS: In the final follow-up a significant lower TslewC was observed among patients in the nonsurvivor compared with the other group (P<.001). Tests to find an optimal prognostic threshold of the TslewC yielded the value of 26 mV. CONCLUSION: TslewC functioned as a prognostic factor after OHT. Further studies must provide a prognostic threshold to avoid patient visits all 4 weeks. Patients would only have to be admitted to the hospital if the TslewC was under this prognostic threshold.     

Gemcitabine does not prevent acute rejection of the transplanted liver in rats

Abstract Our study was designed to determine effect of gemcitabine on acute rejection of liver in rats. Liver transplantation was performed in rats of the Dark Agouti (DA) and Lewis (LEW) strains. Recipients were divided into three groups: A, DA-to-LEW without immunosuppression; B, DA-to-LEW, treated with cyclosporine A; C, DA-to-LEW, treated with gemcitabine. Immunosuppressants were subcutaneously injected for seven consecutive days after transplantation. On day 7, blood samples and liver graft tissue specimens were harvested. Group A showed severe rejection changes (RAI 8/9); in group B no rejection changes were present (RAI 0/9), and in group C moderate rejection changes were observed (RAI 6/9). Differences were significant between B vs C and A vs C groups; P >0.05. Serum creatinine and urea levels in the gemcitabine group were significantly lower than those in the cyclosporine A group. We did not confirm gemcitabine ability to prevent liver allograft rejection.     

Gemcitabine does not prevent acute rejection of the transplanted liver in rats

Our study was designed to determine effect of gemcitabine on acute rejection of liver in rats. Liver transplantation was performed in rats of the Dark Agouti (DA) and Lewis (LEW) strains. Recipients were divided into three groups: A, DA-to-LEW without immunosuppression; B, DA-to-LEW, treated with cyclosporine A; C, DA-to-LEW, treated with gemcitabine. Immunosuppressants were subcutaneously injected for seven consecutive days after transplantation. On day 7, blood samples and liver graft tissue specimens were harvested. Group A showed severe rejection changes (RAI 8/9); in group B no rejection changes were present (RAI 0/9), and in group C moderate rejection changes were observed (RAI 6/9). Differences were significant between B vs C and A vs C groups; P<0.05. Serum creatinine and urea levels in the gemcitabine group were significantly lower than those in the cyclosporine A group. We did not confirm gemcitabine ability to prevent liver allograft rejection.     

烧伤休克犬肠黏膜血流量动态监测方法的研究

目的：建立一种可动态监测实验动物肠黏膜血流量的方法。方法：8只成年雄性Beagle犬,无菌手术行十二指肠造口置管和动、静脉置管术,24h后给予丙泊酚短时静脉麻醉,凝固汽油燃烧制成35%TBSAⅢ度烧伤模型,烧伤后30 min按Parkland公式进行静脉液体复苏,在烧伤前和烧伤后2、4、8、24、48、72 h共7个时间点将激光多普勒血流仪（LDF）的光纤探头通过造口置入十二指肠腔,测量十二指肠黏膜血流量（DMBF）,同时采用张力测定法测量胃黏膜二氧化碳分压（PgCO2）,采用热稀释法测量心排血量（CO）,统计学方法分析DMBF测量值与PgCO_2和CO的相关性。结果：所有十二指肠造口术均一次成功,动物死亡率为零。烧伤后2 h DMBF下降了24%,随后逐渐恢复,至72 h仍较伤前降低16%;PgCO2伤后迅速升高,伤后2 h较伤前升高138%,然后缓慢降低,72 h仍较伤前升高67%;而CO变化不明显。烧伤后动物DMBF与PgCO2呈负相关并有统计学意义（r =-0.8075,P〈0.05）,DMBF与CO无统计学相关性（r=0.1171,P〉0.05）。结论：本实验所建立的肠黏膜血流量监测法简便易行,测量结果符合动物烧伤后病程生理变化,可信度较高,适用于犬、猪等大型动肠黏膜血流量的连续监测。