Inhibition of carotid artery neointimal formation with intravenous microbubbles.

Because therapeutic gene products such as synthetic antisense oligodeoxynucleotides (ODN) bind to albumin-coated microbubbles, we sought to determine whether IV perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles could target their delivery to the carotid artery following balloon injury. In 5 pigs, the concentration of ODN taken up within the carotid vascular wall was found to be significantly increased when the IV antisense (ODN) was administered bound to PESDA (ODN-PESDA), and while transcutaneous low-frequency (20 kHz) ultrasound was applied over the carotid artery. Based on these results, a chronic model was then developed, in which 21 pigs received either IV ODN-PESDA, ODN alone, or control, following carotid balloon injury. At 30 days following balloon injury, percent area stenosis was only 8 +/- 2% in the ODN-PESDA groups compared to 19 +/- 8% and 28 +/- 3% in the other groups (p < 0.01). IV PESDA may be a method of noninvasively targeting the delivery of therapeutic genes.

Isolated intestinal transplantation for intestinal failure.

OBJECTIVE: Parenteral nutrition sustains life in patients with intestinal failure. However, some experience life-threatening complications from parenteral nutrition, and in these individuals intestinal transplantation may be lifesaving. METHODS: This is a retrospective review of 28 consecutive isolated small bowel transplants performed in eight adults and 20 children between December 1993 and June 1998 at the University of Nebraska Medical Center. RESULTS: The 1-yr patient and graft survivals were 93% and 71%, respectively. The causes of graft loss were hyperacute rejection (n = 1), acute rejection (n = 5), vascular thrombosis (n = 1), and patient death (n = 1). The median length of time required until full enteral nutrition was 27 days. All 28 patients have experienced acute rejection of their small bowel grafts and rejection led to graft failure in five. Jaundice and/or hepatic fibrosis was present preoperatively in 17 of the 28 recipients and hyperbilirubinemia was completely reversed in all patients with functional grafts within 4 months of transplantation. Three patients developed post-transplant lymphoproliferative disease (11%). Three recipients developed cytomegalovirus enteritis and all were successfully treated. CONCLUSIONS: Patient survival after intestinal transplantation is comparable to parenteral nutrition for patients with intestinal failure. Better immunosuppressive regimens are needed to decrease the risk of graft loss from acute rejection. The incidence of posttransplant lymphoproliferative disorder is higher after intestinal transplantation than after other solid organ transplants and the risk of cytomegalovirus enteritis is low with the use of cytomegalovirus seronegative donors. Liver dysfunction in the absence of established cirrhosis can be reversed.

Effect of surrogate tolerogenesis on the vascular rejection of pig heart xenografts.

BACKGROUND: Organ xenografts are fulminantly rejected by antibody-mediated vascular rejection. Surrogate tolerogenesis (ST), the induction of tolerance within the donor, is effective with aorta xenografts. This preliminary study assesses the effect of ST on preformed antibodies and rejection of porcine heart xenografts. METHODS: Tolerance to the donor pig was induced by infusing recipient marrow into fetal pigs. Later, pig splenocytes were transfused and heterotopic pig hearts transplanted using chimeric or nonchimeric pigs. Anti-pig antibodies were assessed. RESULTS: With ST alone, xenografts developed cellular rejection at 4-6 days, whereas control grafts developed vascular rejection at 3-4 days (cellular vs. vascular, P<0.03). There was a reduction in preformed antibodies (P<0.03). ST combined with moderate cyclosporine prevented rejection at 9+ and 25 days in sensitized recipients compared with vascular rejection at 0.5-2 days for controls (P<0.07). CONCLUSIONS: ST seems to provide protection against vascular rejection. The cellular rejection seems sensitive to cyclosporine.

Correlation of mucosal disaccharidase activities with histology in evaluation of rejection following intestinal transplantation.

Following intestinal transplantation, we have found that recovery from severe rejection may be difficult to identify. In this study we sought to ascertain whether concurrent determination of mucosal disaccharidase activities and histologic assessment improves the accuracy of diagnosis of rejection. Histologic changes were graded blindly using a standard set of diagnostic criteria, and these changes were compared over time to maltase, sucrase, lactase, and palatinase activities in four pediatric patients under treatment for severe rejection. The histologic criteria, which included magnitude of enterocyte loss, degree of granulation tissue, severity of villus atrophy, and frequency of apoptosis and cryptitis, were found to correlate with one another over time irrespective of outcome (r = 0.72 to r = 0.85). Enzyme activities were also correlated with each other over time (r = 0.64 to r = 0.80). However, the correlation between histologic diagnosis and enzyme activity was weaker (r = -0.48 to r = -0.57). Furthermore, neither histologic nor enzyme evaluation early in the course of rejection predicted ultimate clinical outcome. The results of this investigation show that determination of mucosal disaccharidase activity provides no additional useful information concerning efficacy of anti-rejection therapy as compared to histologic analysis alone.

Solitary pancreas transplantation. Experience with 62 consecutive cases.

OBJECTIVE: To determine the safety and efficacy of solitary pancreas transplantation in the treatment of IDDM. RESEARCH DESIGN AND METHODS: A single-center retrospective case series of 62 consecutive solitary pancreas transplants (20 sequential pancreas after kidney, 42 pancreas transplants alone) performed in 57 adult IDDM patients was studied. Indications for solitary pancreas transplantation were 1) the presence of two or more overt diabetic complications and/or 2) glucose hyperlability with hypoglycemic unawareness and impaired quality of life. The recipient group consisted of 31 men and 26 women with a mean age of 38 years (range 25-62) and a mean duration of diabetes of 26 years (range 14-52). Mean pretransplant glycohemoglobin level was 9.9 +/- 2.6%. Organ acceptance was restricted to ideal donors and man-dated a minimum of a two-antigen match (mean human leukocyte antigen ABDR match 2.7). The mean cold ischemia time was 16.6 h. Whole-organ pancreas transplantation was performed with bladder drainage by the duodenal segment technique. All patients were managed with either triple or quadruple immunosuppression. Monitoring included prospective urine cytology as well as cystoscopic transduodenal needle biopsies. RESULTS: The mean length of initial hospital stay was 18 days, and mean hospital charges were $106,341. The incidences of rejection, infection, and surgical complications were 70, 55, and 47%, respectively. Overall patient and graft survival rates were 86 and 52%, respectively, with a mean follow-up of 28 months. All patients with functioning grafts had excellent metabolic control (mean glycohemoglobin level 5.1%) and achieved good rehabilitation. CONCLUSIONS: Despite morbidity, solitary pancreas transplantation can be performed with improving success, can enhance quality of life, and can offer an opportunity to arrest secondary diabetic complications.

Duodenal segment complications in vascularized pancreas transplantation.

Bladder drainage by the duodenal segment (DS) technique is currently the preferred method of pancreas transplantation (PTX) but is associated with unique complications. Over a 7-year period, 191 diabetic patients underwent 201 whole-organ PTXs with bladder drainage using a 6 to 8 cm length of DS as an exocrine conduit. A retrospective chart review was performed to document all DS morbidity. DS complications occurred in 38 cases (19%). Twelve patients developed DS leaks and required operative repair. DS bleeding was documented in 26 cases, necessitating cystoscopy in 22 patients and open repair in eight patients for significant hematuria. Cytomegalovirus (CMV) duodenitis was diagnosed in seven cases, with four presenting as DS leaks and three with hematuria. Five patients experienced ampullary obstruction early after PTX. Rejection of the DS was confirmed by biopsy in 13 patients, including eight cases of acute and five cases of chronic rejection. Two patients had stone formation from the DS staple line. Enteric conversion was performed in five patients for DS abnormalities (leaks in 2 cases, bleeding in 2, and CMV duodenitis in 1). Among patients with DS complications, patient survival is 84% and pancreas graft survival is 68% after a mean follow-up of 44+/-12 months. Complications related to the DS remain an important source of morbidity but rarely cause death after PTX. In spite of unique side effects, transplantation of the DS remains an acceptable alternative for exocrine drainage after PTX.

Pancreas allograft rejection: correlation of transduodenal core biopsy with Doppler resistive index.

PURPOSE: To determine the usefulness of sonographically obtained resistive indexes (RIs) in the diagnosis of pancreas allograft rejection. MATERIALS AND METHODS: Findings were studied from 78 transduodenal pancreas allograft biopsies that were ultrasound-guided and cystoscopically directed. The 78 biopsies included 40 that were compared directly with baseline RI data. Biopsies were categorized by result and correlated with concurrent RIs (including 26 RIs obtained within 24 hours of biopsy) with the chi2 test for categoric variables and the Student t test for continuous variables. Sensitivity, specificity, and positive and negative predictive values were calculated with standardized formulas. RESULTS: The mean RIs between the no rejection, mild acute rejection, and moderate acute rejection groups were not statistically significantly different; however, the mean RI associated with chronic rejection was statistically significantly higher (P < .05) than that in the other groups. The sensitivity, specificity, and positive and negative predictive values of either an elevated RI (> 0.70) or greater than 10% increase in the RI above the baseline value in the diagnosis of acute rejection were approximately 50%. CONCLUSION: Neither the absolute level of the RI nor the relative increase was correlated with acute rejection proved at biopsy. Changes in RIs after pancreas transplantation were a poor indicator of acute rejection, but the absolute value of the RI was elevated in cases of chronic rejection.

Allograft vascular disease: comparison of heart and other grafted organs.

A striking resemblance exists between the vasculopathy in several different allografts. The arteriopathy of epicardial coronary arteries is diffuse, involving proximal, distal, and small branch segments in a generally concentric pattern of intimal thickening. Smooth muscle cells in a lipid- and glycosaminoglycan-rich matrix are the predominant components of this expanded intima. Varying amounts of collagen are present, more being present late posttransplant. A superficial and, to a lesser degree, deep, bandlike infiltrate of T cells and macrophages is uniformly present, although it is somewhat more prominent in early lesions as compared to more severely narrowed arteries from longer-term, susceptible grafts. The media is likewise altered by areas of lipid and glycosaminoglycan deposition associated with smooth muscle cell loss and phenotypic modulation. The media is altered in an outside-to-inside direction, with percolation of adventitial leukocytes into the outer media. Virtually all of the coronary features are seen in the medium to large arteries of liver, pancreas, and kidney allografts. Chronic rejection in lung allografts is manifest by obliterative bronchiolitis; vascular changes, although architecturally similar, are somewhat less common and result in less-severe luminal narrowing. The role of allograft vasculopathy in chronic lung rejection is thus less certain. A finding perhaps unique to epicardial coronary arteries of heart allografts is the presence of eccentric lesions more typical of native atherosclerosis. Many of the latter grafts probably have preexistent, undetected donor disease. Sequential evaluation of vascular changes is limited in human biopsy material by their general absence in endomyocardial or core liver needle specimens. Fortunately, vascular changes can be detected in some renal and pancreas core needle biopsies, and these findings may provide an avenue for monitoring the effectiveness of immunosuppressive therapy, antiviral or lipid-altering therapies, or modifications of smooth muscle cell proliferation and glycosaminoglycan deposition yet to be developed.

Experience with protocol biopsies after solitary pancreas transplantation.

The early detection of allograft rejection remains elusive after solitary pancreas transplantation (PTX). We have previously described a modified technique of cystoscopic transduodenal PTX biopsy using the Biopty gun under ultrasound guidance. During the last 2 years, we performed 24 solitary PTXs with prospective protocol biopsy monitoring as well as biopsies performed whenever clinically indicated. The study group included 17 pancreas transplants alone, 6 sequential pancreas after kidney transplants, and 1 sequential pancreas after liver transplant. Five patients received pancreas retransplants. A total of 92 cystoscopically directed core PTX biopsies were performed, including 50 protocol biopsies (mean 2.1 per patient). Protocol biopsies were performed at 1 month (19), 2 months (3), 3 months (20), 6 months (7), and 12 months (1) after PTX. Adequate PTX tissue for histopathologic examination was obtained in 49 cases (98%). Biopsy findings included no rejection (34), mild rejection (13), pancreatitis (1), and cytomegalovirus infection (1). Overall, 15 of the 49 evaluable biopsies (31%) had significant histopathologic findings. All but 1 of the cases of mild rejection were treated with bolus steroids. Eight of these patients subsequently developed recurrent biopsy-proven rejection within 2 months; 5 grafts were subsequently lost to rejection between 3 and 13 months after PTX. Three biopsy complications occurred: 1 hematoma, 1 pancreatitis, and 1 ileus. Patient survival is 96% and PTX graft survival (complete insulin independence) is 75% after a mean follow-up of 15 months. In the remaining 42 clinically indicated biopsies, 3 were insufficient, 8 showed no rejection, and 31 (79%) had rejection. In half of these cases, the rejection was graded as moderate to severe. In conclusion, prospective monitoring with protocol PTX biopsies may result in the earlier detection of allograft rejection and have a direct effect on improving results after solitary PTX.

Prominence of coronary arterial wall lipids in human heart allografts. Implications for pathogenesis of allograft arteriopathy.

Transplant arteriopathy is a major late complication in human heart allograft recipients and the pathogenesis of such arteriopathy remains uncertain. The degree to which lipids and atheromata are involved in the arteriopathic lesions remains unsettled, and there is uncertainty regarding the significance of insudation or retention of lipids within the coronary artery walls of transplanted hearts. On current immunosuppressive regimens, most patients experience an increased serum total cholesterol and low-density lipoprotein cholesterol after transplant. Elevation of these blood lipids has an undetermined relationship to arteriopathy. We carried out morphological, morphometric, immunohistochemical, ultrastructural, and biochemical studies of particular coronary artery segments from 23 unselected explant or autopsy allografts and donor age-matched native coronary controls. Patients died of cardiac and non-cardiac reasons over a period of 4 to 1610 days after transplant. Atheromata were frequent, and diffuse intra- and extra-cellular accumulation of lipids in both intimal and medial walls was documented by oil red O positivity, immunohistochemical staining (muscle-specific alpha-actin), transmission and scanning electron microscopy, and biochemical analysis. Mean total cholesterol, esterified cholesterol, free cholesterol, and phospholipid content (microgram/cm2 intimal surface area) and concentration (microgram/mg dry defatted weight) in arteriopathic coronaries were > 10-fold higher than in comparable native coronary segments. Extent of lipids in the arterial walls was highly correlated with digitized percent luminal narrowing, mean daily and cumulative cyclosporin dose, and mean cumulative prednisone dose. Our data suggests strongly that lipid accumulation is an important early and persistent phenomenon in the development of transplant arteriopathy.

Infrequency of cytomegalovirus genome in coronary arteriopathy of human heart allografts.

In heart transplantation, long-term engraftment success is severely limited by the rapid development of obliterative disease of the coronary arteries. Data from various groups have been suggestive of a pathogenetic role of herpesviruses, particularly human cytomegalovirus, in accelerated allograft coronary artery disease; however, results are not yet conclusive. This study examines the hypothesis that human cytomegalovirus infection of allograft tissues is related pathogenetically and directly to accelerated coronary artery disease. Using in situ DNA hybridization and polymerase chain reaction, we examined particular coronary artery segments from 41 human heart allografts (ranging from 4 days to greater than 4 years after transplantation; mean, 457 days) and 22 donor age- and gender-comparable, coronary site-matched trauma victims for presence of human cytomegalovirus DNA. Human cytomegalovirus genome was detected in 8 of 41 (19.5%) allografts and in 1 of 22 (4.5%) control hearts. This difference in positivity was not statistically significant (P = 0.10). In the human cytomegalovirus-positive hearts, viral genome was localized to perivascular myocardium or coronary artery media or adventitia. Human cytomegalovirus genome was not detected in arterial intima of any allograft or control heart, although human cytomegalovirus genome was readily identified within intima of small pulmonary arteries from lung tissue with human cytomegalovirus pneumonitis. By statistical analyses, the presence of human cytomegalovirus genome was not associated with the nature or digitized extent of transplant arteriopathy, evidence of rejection, allograft recipient or donor serological data suggestive of human cytomegalovirus infection, duration of allograft implantation, or causes of death or retransplantation. Thus, our data indicate a low frequency of detectable human cytomegalovirus genome in accelerated coronary artery disease and do not support a direct role for human cytomegalovirus in vascular wall infection or in the development of accelerated coronary artery disease.

Rejection with duodenal rupture after solitary pancreas transplantation: an unusual cause of severe hematuria.

A common urologic complication after pancreas transplantation with bladder drainage is hematuria. However, hematuria is usually mild and self-limiting and rarely requires open surgical intervention. We report an unusual case of refractory hematuria that began 17 days after solitary pancreas transplantation due to severe rejection. The patient developed severe duodenal segment swelling with mucosal rupture that eventually required operative therapy. This case is illustrative of the diagnosis and management of gross hematuria after pancreas transplantation and demonstrates the limitations of cystoscopic techniques. This unusual complication must be considered in the differential diagnosis of refractory hematuria with pancreas allograft dysfunction and may represent a problem unique to solitary pancreas transplantation until better immunosuppressive strategies are available.