Immunomodulation in transplantation with photopheresis

Photopheresis is a technique in which peripheral blood mononuclear cells, in the presence of a photoactivatable compound, are exposed extracorporeally to ultraviolet A light and reinfused, inducing a host autoregulatory immune response. Experimental work and ongoing clinical studies are helping to define the role of this novel, safe, and non-toxic immunomodulating technology in the field of transplantation.

Orbital myositis, vitiligo, and giant cell myocarditis

Giant cell myocarditis is a rare idiopathic inflammatory heart disease characterized histologically by multinucleated giant cells, and clinically by rapid progressive heart failure, arrhythmias, or sudden death, often within hours to days of initial symptoms. There are two previously reported cases of giant cell myocarditis with idiopathic orbital myositis. We report a similar case in a patient who also had vitiligo, a diagnostic endomyocardial biopsy, and survival because of a cardiac transplant. Giant cell myocarditis should be monitored for in the course of inflammatory orbital myopathy because of its life-threatening fulminant course.

Safe application of diagnostic laparoscopy during biventricular assistance

We performed diagnostic laparoscopy in a patient who was critically unstable while on an ABIOMED BVS 5000 biventricular assist system. A relatively unique feature of the ABIOMED is the venous return being dependent only on gravity and the drawing force of venous return being the height of the inflow cannula compared with the level of the ABIOMED blood pump assembly; this did not preclude the use of pneumoperitoneum necessary for laparoscopy. The safe application of diagnostic laparoscopy in patients on a ventricular assist device is of importance in an era of increasing use of these devices and the increased potential for intraabdominal complications in this population.

Surgical management of cardiac pheochromocytoma. Resection versus transplantation

OBJECTIVE

The authors review their experience and that of others who have reported cases in the literature on the surgical management of cardiac pheochromocytomas.

SUMMARY BACKGROUND DATA

Cardiac pheochromocytomas are rare cathecolamine-producing tumors that can be densely adherent to myocardium. Because resection can be associated with significant morbidity, we sought to determine the best mode of treatment for these difficult tumors.

METHOD

The authors reviewed the experience for management of cardiac pheochromocytomas in their two institutions and those reported in the literature. Follow-up was available for 21 of 26 patients up to 9 years after resection.

RESULTS

Twenty-five patients had reconstruction of the native heart; five (20%) died intraoperatively from hemorrhage, one (4%) died postoperatively from sepsis, three (12%) sustained myocardial infarction, one (4%) required a mitral valve replacement, and three (12%) had incomplete resections, two of whom subsequently developed metastatic disease and died. One patient, thought to be a high risk for resection, received an orthotopic heart transplantation.

CONCLUSIONS

Surgical resection of cardiac pheochromocytomas can be performed successfully. However, resection of lesions that aggressively invade adjacent myocardium is associated with significant mortality and inadequate control of the neoplasm. Cardiac transplantation should be available as an option before embarking on resection, and it should be performed if mandated by intraoperative findings.

Increased early mortality in women undergoing cardiac transplantation

BACKGROUND

To evaluate factors that explain sex differences affecting mortality after cardiac transplantation, a retrospective analysis of adult patients undergoing orthotopic cardiac transplantation was undertaken at the Columbia-Presbyterian Medical Center.

METHODS AND RESULTS

The study population consisted of 379 patients (75 women, 304 men) > or = 18 years of age who survived for > or = 48 hours after undergoing orthotopic cardiac transplantation between March 1985 and March 1992. The following were analyzed: incidence of death and treated rejection episodes, donor and recipient cytomegalovirus (CMV) matches, use of OKT3 induction therapy, and donor and recipient HLA mismatches. Women 49 +/- 12 years old and men 47 +/- 12 years old were characterized by differences in race and diagnosis. Women were more likely to be nonwhite (P < .01) and have idiopathic cardiomyopathy than were men (P < .01). A trend toward an increase in first-year rejection frequency was seen in women compared with men (P = .08). Overall actuarial survival was significantly reduced in women after transplantation (P < .05). At 36 months, female actuarial survival was 64 +/- 7% versus 76 +/- 3% for men (P < .05). The majority of patients in this study did not receive CMV prophylaxis. Univariate analysis revealed that only CMV(+) donor status and the use of OKT3 induction therapy affected survival in women. Multivariate analysis revealed a marked reduction in survival in female recipients of CMV(+) donors given OKT3 induction therapy. At 36 months, only 25% of women were still alive compared with 86% of women with neither risk factor (P < .001). Even without OKT3 induction there was markedly reduced survival in women with mismatched CMV status, ie, CMV(-) recipients of CMV(+) donors; 17% survival after 36 months versus 86% in women who were CMV(+) recipients (P < .05). Although at this institution during the study time period, CMV prophylaxis was not routinely employed and OKT3 induction was selectively used in higher-risk patients, conclusions regarding differences in outcome that are sex dependent are valid.

CONCLUSIONS

(1) Women are at risk for reduced actuarial survival up to 3 years after cardiac transplantation. (2) Univariate analysis shows that women are selectively at risk for death when receiving hearts from CMV(+) donors and after receiving OKT3 induction therapy. (3) Multivariate analysis reveals that women are at even greater risk for death when receiving hearts from CMV(+) donors in conjunction with OKT3 induction therapy. (4) In the absence of OKT3 use, the greatest risk of death occurs in CMV(-) women transplanted with CMV(+) donor hearts. (5) When female to male survival curves are compared, factors that influenced survival in women did not appear to be problematic in men.

Lobar transplantation. Indications, technique, and outcome

Lobar transplantation represents a therapeutic option for children and some adults with severe end-stage pulmonary disease. Six patients including two neonates, three children, and one adult underwent lobar transplantation. Ages ranged from 17 days to 21 years. Transplant procedures were unilateral in the neonates and two of the children and bilateral in the child and adult who had cystic fibrosis. The donor lobes were from cadavers in the two neonates and living related donors in the children and the adult. Unilateral grafts involved use of the right upper lobe in the 12-year-old patient with bronchopulmonary dysplasia; right middle lobe with a ventricular septal defect repair in the 4-year-old patient with Eisenmenger's syndrome, left upper lobe in the 28-day-old patient with primary pulmonary hypertension, and the right upper and middle lobes in the 17-day-old patient with diaphragmatic hernia. Bilateral lobar transplantations were performed with the right lower and left lower lobes in the two patients with cystic fibrosis (aged 13 and 21 years). The two neonates underwent emergency transplantation with the use of extracorporeal membrane oxygenation as a bridge. Perioperative survival was 83%, with only the 4-year-old patient with ventricular septal defect/Eisenmenger's syndrome dying early. No airway complications were observed. The unilateral grafts received most of the blood flow as shown by perfusion scanning (range 74% to 99%). Living related donor complications included prolonged air leaks (> 6 days) in two patients. In urgent situations, such as an infant requiring extracorporeal membrane oxygenation, and in the existing milieu of donor shortage, lobar transplantation (living related or cadaveric) is a surgically feasible procedure and can provide a donor source in the limited time frame of these clinical situations. Bilateral lobe transplantation may be a viable option for patients with cystic fibrosis and life-threatening respiratory decompensation.

Influence of HLA mismatch on rejection after heart transplantation: a multiinstitutional study. The Cardiac Transplant Research Database Group

HLA mismatch has been shown to influence survival after heart transplantation. No large multicenter study has examined the effect of HLA mismatch on cardiac allograft rejection. HLA mismatch and other potential risk factors for rejection were analyzed in data from 27 institutions (1719 patients) participating in the Cardiac Transplant Research Database between January 1, 1990, and June 30, 1992. Complete HLA information on the A, B, and DR loci was available for both donor and recipient in 1190 patients. Of these, 619 (52%) had five or six mismatches; 68 (6%) had zero, one, or two mismatches. The mean number of mismatches was 4.4 and did not differ, regardless of donor-recipient race match (4.3 versus 4.8, p = 0.19). According to multivariate analysis, risk factors for time to first rejection included younger recipient age (p < 0.0001), female gender of both donor and recipient (p < 0.0006), number of HLA mismatches (p = 0.013) and black recipient race (p < 0.004). Patients with zero, one, or two mismatches (n = 67) had a 54% freedom from rejection at 1 year versus 36% for patients with three or more mismatches (n = 1005, p = 0.02). HLA mismatch number did not affect time to first rejection or rejection frequency among black patients. Risk factors (by multivariate analysis) for death or retransplantation because of rejection included female recipient gender (p = 0.008) and black recipient race (p = 0.006). The probability of rejection-related death or retransplantation by 2 years was 0% with zero, one, or two HLA mismatches versus 5% for three to six mismatches (p = 0.14). These findings should stimulate further investigation of methods to clarify the HLA effect in heart transplantation and eventually the use of HLA typing in donor-recipient selection.

Living-related donor lobectomy for bilateral lobar transplantation in patients with cystic fibrosis

Donor lobectomy has been performed in 14 patients enabling 7 recipients with cystic fibrosis to undergo bilateral living-related lobar pulmonary transplantation. Donors included 11 patients, 2 brothers, and 1 uncle. Donor mean age was 43 years (range 24 to 55 years). Their mean height and weight was 170 cm (range, 169 to 180 cm) and 72.4 kg (range, 55 to 90 kg), respectively, compared with 161 cm (range, 140 to 175 cm) and 42.4 kg (range, 27 to 55 kg), respectively, in the recipient group. Donor pulmonary evaluation consisted of a history and physical examination, chest roentgenogram and computed tomographic scan, spirometry with arterial blood gas measurement, echocardiography, and perfusion scanning. From each pair of donors, one was selected for right lower lobectomy and the other for left lower lobectomy. Standard lobectomy techniques were modified to facilitate implantation and optimize preservation of the donor lobes. On the right side, the middle lobe was removed and discarded in the first three donors to provide an adequate cuff of pulmonary artery and bronchus for implantation. With increased experience, this has proved not to be necessary. There have been no deaths and no long-term complications in the donor group. Prolonged postoperative air leaks occurred in the 3 patients who underwent right lower and middle lobectomies. All donors have been able to resume their previous lifestyles. Living-related donor lobectomy provides an alternative to cadaveric organs in select patients in need of pulmonary transplantation.

Myocardial perfusion scintigraphy in heart transplant recipients with and without allograft atherosclerosis: a comparison of thallium-201 and technetium 99m sestamibi

Our objectives were to assess the comparative value of thallium-201 and technetium 99m sestamibi for the detection of cardiac allograft atherosclerosis and the left ventricular ejection fraction response to exercise in heart transplant recipients with and without allograft atherosclerosis. Allograft atherosclerosis is the critical factor limiting long-term survival in heart transplant recipients. Annual coronary angiography is invasive and expensive. A noninvasive test to detect allograft atherosclerosis would be clinically useful. Treadmill exercise testing followed by myocardial perfusion single-photon computed tomographic imaging was performed in 25 heart transplant recipients. All patients underwent coronary angiography. Group 1 (13 patients) had angiographic coronary artery disease; group 2 (12 patients) did not. Eighteen patients underwent two exercise tests to equivalent work loads with thallium-201 and technetium 99m sestamibi; seven patients underwent only thallium-201 imaging. First-pass left ventricular ejection fraction was measured during injection of technetium 99m sestamibi. In group 1, 10 of 13 patients had abnormal thallium-201 scans. There was no significant difference in the number of patients who had abnormal thallium-201 (7/10) and technetium 99m sestamibi scans (6/10). Fifty-two percent (12/23) of discordantly scored segments were reversible on thallium-201 and fixed on technetium 99m sestamibi imaging compared with the opposite (0%; 0/23) (p < 0.01). All patients in group 2 had normal perfusion scans. There were no false-positive scans.(ABSTRACT TRUNCATED AT 250 WORDS)

Pediatric lung transplantation

As the first decade of successful clinical lung transplantation draws to a close, the number of patients who are able to benefit from it continues to increase. Pulmonary transplantation in the pediatric age group is possible for an expanding range of diagnoses currently known to cause end-stage lung disease. However, more experience will be required before the answers to a number of clinical problems are found. The following issues are particularly pertinent to the pediatric age group: (1) Controversy still exists as to the most appropriate operation for certain clinical situations (eg, single- or double-lung transplants for primary pulmonary hypertension, or secondary pulmonary hypertension after cardiac repair). These decisions are made based on physiological considerations as well as donor availability and the need to use the donor pool as efficiently as possible. (2) Technical controversies in pediatric lung transplantation include the optimal technique for performing the bronchial anastomosis in a manner that will permit healing without stenosis of the airway. Cardiopulmonary bypass is required for most lung transplants in children. (3) OB continues to plague the long-term results of lung transplantation and may be more common in the pediatric age group. OB may respond to increased immunosuppression. (4) Lobar transplantation in children may be an effective method of increasing the availability of donors. More experience will be necessary to further refine this technique.

Posttransplantation lymphoproliferative disorders treated with cyclophosphamide-doxorubicin-vincristine-prednisone chemotherapy

BACKGROUND

Posttransplantation lymphoproliferative disorders after solid organ transplantation are a serious complication occurring in 1-10% of patients. Different therapies have been used, but the optimal treatment is unknown. There is relatively little information in the literature on the experience with cytotoxic chemotherapy.

METHODS

The disease stage of patients with biopsy-documented posttransplantation lymphoproliferative was determined with standard methods to establish the extent of the disease. Patients in whom the disease failed to regress after initial management, which included reduction in immunosuppression, were treated with a combination chemotherapy regimen consisting of six cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Response to therapy was determined by following previously defined sites of disease with appropriate tests. Patients were maintained on a reduced dose of immunosuppressants.

RESULTS

In the four patients studied, lymphoproliferative disorders developed after heart (three cases) or lung (one case) transplantation, which did not regress after immunosuppression was reduced. All four experienced a complete remission with CHOP chemotherapy, which continued at 3, 13+, 20 and 30+ months after completion of treatment. One patient died of sepsis after completing therapy at a point when his leukocyte count was normal, and no evidence of posttransplantation lymphoproliferative disorder was found at autopsy. A second patient died of liver failure with no clinical evidence of lymphoproliferative disorder.

CONCLUSION

Although this is a small series, it demonstrates that patients with posttransplantation lymphoproliferative disorders may respond to cytotoxic chemotherapy. The duration of response is undetermined.

Clinical experience with cardiac retransplantation

Although more than 560 patients worldwide have undergone cardiac retransplantation, few studies of this population have been reported. To evaluate the risk of cardiac retransplantation and to better establish selection criteria, we reviewed the records of all patients who underwent retransplantation at the Columbia-Presbyterian Medical Center. Of 431 patients who underwent transplantation between February 1977 and March 1991, 408 underwent the procedure in the era of cyclosporine-based immunosuppression. Thirteen of these 408 patients underwent retransplantation (including one patient who received a third graft). Indications for the 14 retransplantations included transplant coronary artery disease (n = 8), rejection (n = 5), and intraoperative graft failure (n = 1). Immunosuppression and follow-up protocols used in this cohort were similar to those in the primary transplantation population. No significant differences were found in either actuarial survival between primary transplant recipients (75.1% +/- 2.2% at 1 year and 71.3% +/- 2.4% at 2 years) and patients who underwent retransplantation (71.4% +/- 12.1% at 1 year and 59.5% +/- 14.8% at 2 years) or in linearized rates of rejection and actuarial freedom from rejection between the two groups. No differences between these groups were found with regard to age, sex, race, origin of end-stage heart disease, or early (< 30 day) mortality. The origin of primary graft failure did not correlate with survival outcome in the retransplantation cohort. Follow-up time for patients having primary transplantation ranged from 0 to 8 years (mean 24 months) with a cumulative patient follow-up of 830 patient-years; follow-up time for patients who underwent retransplantation ranged from 0 to 3 years (mean 8.1 months) with a cumulative patient follow-up of 9.5 patient-years. Approximately 50% of patients in both groups had at least one rejection episode by 3 months. Within the limited time period studied after retransplantation, only one patient had transplant coronary artery disease, approximately 27 months after her first retransplantation procedure for acute rejection. These results indicate that the prognosis for patients undergoing cardiac retransplantation is good for patients for whom the indication for retransplantation is identified more than 30 days after initial transplantation.

Management of lymphoproliferative disorders after cardiac transplantation

We conducted a retrospective study of 516 cardiac recipients who underwent transplantation between April 1983 and April 1992, 19 of whom had development of post-transplantation lymphoproliferative disorders (PTLDs). These 19 patients presented with involvement of lung (5), gastrointestinal tract (5), disseminated disease (6), and adenoids and lymph nodes (3). B-cell proliferations ranging from an atypical hyperplasia to malignant lymphoma developed in 18 patients, and mixed cellularity Hodgkin's disease developed in 1 patient. The 19 patients with PTLD displayed a predominance of both women and cardiomyopathy as the indication for transplantation when compared with two separate control populations. No correlation was found between demographic criteria analyzed and (1) early versus late diagnosis of PTLD after transplantation, (2) the site of PTLD involvement, or (3) the histopathologic category of the PTLD lesion. Patients with gastrointestinal tract and lung PTLD involvement enjoyed an improved survival after both transplantation and PTLD diagnosis when compared with patients with PTLD involvement of all other extranodal sites. We report a high incidence of PTLD involving the lung and gastrointestinal tract in our cohort study. These sites of involvement responded better to a reduction in immunosuppression than did the other extranodal sites of involvement.

Effect of anti-HLA antibodies on the long-term survival of heart and kidney allografts

Study of anti-HLA antibodies in a population of 238 primary renal and 199 primary heart allograft recipients showed significant association between development of anti-HLA antibodies and that of chronic allograft rejection. The 5-year renal allograft survival was 70% in recipients without antibodies and 53% in recipients who developed anti-HLA alloantibodies during the first year following transplantation. Heart allograft survival at 5 years was 91% in patients without and 78% in patients with antibodies during the first 12 months posttransplantation. Development of antibodies is associated with acute rejection episodes and probably with the release of soluble HLA antigens.

Effect of recipient gender and race on heart and kidney allograft survival

Study of long-term survival of heart allografts shows that AA males and females have lower graft survival rates than those observed in NAC recipients. Primary kidney allografts in AA males, but not females, also display lower 5-year survival rates compared to those observed in the corresponding populations of NAC. Comparison of graft survival in the overall population of male and female recipients of kidney allografts shows that females have higher graft survival rates, probably as a result of better HLA matching. The level of alloantibody activity in posttransplantation sera is similar in the two populations, suggesting that factors other than HLA mismatching may contribute to the higher degree of graft failure in AA recipients.

Effect of anti-HLA and anti-idiotypic antibodies on the long-term survival of heart and kidney allografts

Long-term survival of heart and kidney allografts is threatened by the development of chronic rejection. Analysis of the relationship between reversible acute rejection episodes and actuarial survival at 5 years showed an inverse correlation suggesting that early cellular events may trigger antibody-mediated chronic rejection. In both heart and kidney allograft recipients producing anti-HLA antibodies we found a significant decrease in the 5-year graft survival rate. However, there was heterogeneity among anti-HLA antibody producers with respect to the development of anti-idiotypic antibodies. The actuarial 5-year graft survival was significantly higher in patients with Ab2 compared to patients without.

Photochemotherapy in human heart transplant recipients at high risk for fatal rejection

Heart transplant recipients in whom high levels of lymphocytotoxic antibodies directed towards a spectrum of histocompatibility antigens develop frequently represent difficult management problems. Recipients of multiple transplants and multiparous females generally form higher levels of panel reactive antibodies, which have been associated with fatal rejection episodes and accelerated graft atherosclerosis. In this study, two multiple transplant patients with preexistent high levels of panel reactive antibodies and two multiparous women who were considered at risk of sensitization were treated with a new form of immunotherapy termed photochemotherapy in addition to conventional immunosuppression. High levels of panel reactive antibodies have been reduced, and patients have suffered few rejection episodes and no infectious complications. This preliminary experience shows that the addition of photochemotherapy to conventional regimens may improve the clinical course of hypersensitized transplant patients without additional immunosuppressive risk.

Effect of complete cardiac denervation on atrial natriuretic factor release in baboons

We investigated the influence of cardiac innervation on atrial natriuretic factor (ANF) release in baboons. For this purpose, plasma ANF levels were measured in control conditions and in response to head-down (-45 degrees) and head-up tilt (+45 degrees) in six anesthetized baboons before and after complete cardiac denervation obtained by orthotopic autotransplantation of the heart. Cardiac denervation did not modify baseline plasma ANF levels (60.4 +/- 17 pg/ml before and 63.1 +/- 16 pg/ml after heart autotransplantation). In contrast the significant ANF responses to changes in central venous pressure (CVP) induced by postural maneuvers (-45 degrees, + 16.2 +/- 4 pg/ml; +45 degrees, -18.5 +/- 4 pg/ml) were markedly altered after cardiac denervation (-45 degrees, +5.8 +/- 2 pg/ml; +45 degrees, -7.6 +/- 1 pg/ml). The changes in CVP and systemic blood pressure evoked by the postural challenges were comparable before and after cardiac denervation. These results demonstrate that cardiac nerves play a role in the control of ANF release.

Predictors of survival after repeat heart transplantation. The Registry of the International Society for Heart and Lung Transplantation, and Contributing Investigators

To examine factors potentially predictive of outcome after repeat heart transplantation, data were analyzed for 449 recipients of second allografts reported to the registry of the International Society for Heart and Lung Transplantation and a matched group of 421 primary transplant recipients. Survival was markedly decreased in repeat transplantation patients (1 year actuarial survival rate, 48% vs 79%; p less than 0.001). Univariate analysis showed no impact on survival of recipient age or gender, ischemic time, or transplant center experience. Accelerated coronary artery disease as the cause of allograft failure, longer interval between transplants, lack of preoperative mechanical assistance, and second transplantation after 1985 were predictive of increased survival after repeat transplantation. An "ideal candidate" defined by these predictive variables had a 1-year survival rate of 64%. In addition to the International Society for Heart and Lung Transplantation registry, a multicenter data base was developed with data for 125 repeat transplant recipients and 1325 primary transplant recipients at 13 transplant centers in the United States. In this group of patients the 1-year survival rate was greater than that in the International Society for Heart and Lung Transplantation registry (60% vs 48%), and the impact of the predictive variables listed previously was decreased. The incidence of rejection, infection, and accelerated coronary artery disease was not different between secondary and primary allograft recipients. Nonskin malignancies occurred more frequently in repeat transplantation patients (8% vs 4%; p less than 0.05). Recipients of second allografts were more likely to have major surgical complications, had a higher level of sensitization to HLA antigens, and were more likely to have a positive donor-specific crossmatch (17% vs 2%). A trend toward improved survival was noted in patients with repetition in the second donor of mismatched HLA antigens present in the first donor (1-year survival rate of 68% vs 47%; p = 0.06). We conclude that longer interval between transplants, accelerated coronary artery disease as cause of allograft loss, and lack of preoperative mechanical assistance are predictive of longer survival after repeat transplantation. Nonetheless, the "ideal candidate" for repeat transplantation has an anticipated survival rate significantly less than that expected for primary transplant recipients.

Relation of HLA antibodies and graft atherosclerosis in human cardiac allograft recipients

Although cyclosporine has helped make heart transplantation a clinical reality, long-term survival remains limited by rejection and graft atherosclerosis. We have previously demonstrated the development of alloreactive lymphocytotoxic antibodies in baboon recipients of heterotopic heart transplants despite cyclosporine administration. The hypothesis of the present study is that cyclosporine-treated human heart transplant recipients are also capable of generating strong humoral immune responses that might adversely affect clinical outcome. Serial serum specimens from 240 heart transplant recipients were tested against a reference panel of 70 cells for anti-HLA lymphocytotoxic antibodies. Patients with serum panel reactive antibody levels greater than 10% were considered antibody producers, whereas those with serum panel reactive antibody levels less than 10% were considered nonproducers. To establish the time course of post-transplantation sensitization, we have tested anti-HLA antibodies in sequential sera at 3-month intervals after transplantation. The 4-year actuarial survival rate of those patients whose panel reactive antibody levels were greater than 10% during the first 6 months after transplantation was 70%, whereas the survival rate of patients whose levels were less than 10% during this time was 93%. The results were significantly different (p less than 0.01). Further heterogeneity among the patients was demonstrated by differential analysis of survival in patients who showed (1) panel reactive antibody levels less than 10% in any of the sera obtained during the first year after transplantation, (2) panel reactive antibody levels greater than 10% in sera obtained during the first 6 months but not thereafter, and (3) panel reactive antibody levels greater than 10% throughout the first year after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Alternative splicing of the mRNA encoding the human cholesteryl ester transfer protein

The plasma cholesteryl ester transfer protein (CETP) is known to facilitate the transfer of lipids between plasma lipoproteins. The human CETP gene is a complex locus encompassing 16 exons. The CETP mRNA is found in liver and small intestine as well as in a variety of peripheral tissues. While the CETP cDNA from human adipose tissue was being cloned, a variant CETP cDNA was discovered which excluded the complete sequence encoded by exon 9, but which was otherwise identical to the full-length CETP cDNA, suggesting modification of the CETP gene transcript by an alternative RNA splicing mechanism. RNase protection analysis of tissue RNA confirmed the presence of exon 9 deleted transcripts and showed that they represented a variable proportion of the total CETP mRNA in various human tissues including adipose tissue (25%), liver (33%), and spleen (46%). Transient expression of the exon 9 deleted cDNA in COS cells or stable expression in CHO cells showed that the protein encoded by the alternatively spliced transcript was inactive in neutral lipid transfer, smaller, and poorly secreted compared to the protein derived from the full-length cDNA. Endo H digestion suggested that the inactive, cell-associated protein was present within the endoplasmic reticulum. The experiments show that the expression of the human CETP gene is modified by alternative splicing of the ninth exon, in a tissue-specific fashion. The function of alternative splicing is unknown but could serve to produce a protein with a function other than plasma neutral lipid transfer, or as an on-off switch to regulate the local concentration of biologically active protein.

University of Wisconsin solution versus crystalloid cardioplegia for human donor heart preservation. A randomized blinded prospective clinical trial

We have previously shown the safety and efficacy of University of Wisconsin solution for hypothermic preservation of the human donor heart in a pilot group of 16 transplant recipients. The present study is a randomized clinical trial comparing University of Wisconsin solution to conventional preservation using crystalloid cardioplegia and saline storage within a 4-hour limit of ischemia. Heart transplant recipients (n = 42) were randomized into two groups: those receiving hearts preserved by University of Wisconsin solution, the UWS group (n = 22), and those receiving hearts preserved in the conventional manner, the CCS group (n = 20). Recipient age, gender, heart disease, and preoperative inotropic support and donor age, gender, and mean ischemic time in hours (UWS 2 hours 36 minutes, range 1 hour 36 minutes to 2 hours 53 minutes; CCS 2 hours 20 minutes, range 1 hour 20 minutes to 2 hours 44 minutes; p = not significant) were similar. Significant differences observed between the two groups included (1) mean time (minutes) from reperfusion to achieve a stable rhythm, (2) need for intraoperative defibrillations, (3) need for transient cardiac pacing, and (4) integrated postoperative creatinine kinase and aspartate aminotransferase release over 48 hours. There was no difference in postoperative electrocardiogram, endomyocardial biopsy, or hemodynamics. One UWS patient died of sepsis and another of a ruptured cerebral aneurysm. UWS is safe for donor organ arrest and preservation despite high viscosity and potassium concentration. When compared with CCS hearts, hearts preserved in UWS regained electrical activity more rapidly and had better myocardial protection as demonstrated by enzymatic analysis. Further investigation is required to determine the effects of UWS preservation on long-term survival, to determine the prevalence of rejection and graft atherosclerosis, and to test the ability of UWS to extend donor ischemic time in human cardiac transplantation.

Beta-adrenergic receptor sensitivity and guanine nucleotide regulatory proteins in transplanted human hearts and autotransplanted baboons

This study was conducted in human subjects and in baboons to assess elements of the beta-adrenergic receptor complex in vivo and in vitro following cardiac transplantation. In human subjects, the concentration at which administered isoproterenol increased heart rate by 25 beats per min was within the normal range (mean, 3.2 +/- 0.4 micrograms). Myocardial biopsies and lymphocytes were obtained from 14 transplant recipients undergoing routine right heart catheterization. The stimulatory guanine nucleotide regulatory protein, Gs, was significantly greater in the lymphocyte than in right ventricular myocardium (5.8 +/- 1.7 vs. 2.0 +/- 0.5 relative to standard rat heart membrane preparation, P less than 0.05). In contrast, Gi was significantly greater in the myocardium than in the lymphocyte (4.2 +/- 1.3 vs. 1.1 +/- 0.3, P less than 0.025). There was no correlation between lymphocyte and cardiac G protein determinations. In the autotransplanted baboon heart, beta-receptors were increased (73 +/- 4 vs. 36 +/- 10 fmol/mg, P less than 0.05). Gs was not significantly different in denervated myocardial tissue vs. control cardiac tissue (1.1 +/- 0.2 vs. 0.8 +/- 0.2, P greater than 0.05). However, the inhibitory G protein, Gi, was significantly greater in transplanted animals (0.4 +/- 0.1 vs. 0.2 +/- 0.04, P less than 0.05). Relative enrichment of a Gi-like protein in the autotransplanted baboon heart was associated with a non-statistically significant trend towards a uniform reduction in basal and Gs-mediated adrenergic effects on adenylate cyclase activity. Despite the lack of biochemical evidence of enhanced beta-adrenergic receptor-mediated adenylate cyclase coupling, denervation in the autotransplanted baboon was associated with in vitro evidence of chronotropic and inotropic supersensitivity to isoproterenol. The results call into question the notion of adrenergic hypersensitivity in human subjects following cardiac transplantation, indicate the potential role for guanine nucleotide regulatory proteins in mediating responses of the denervated heart, and distinguish between several characteristics of the chronically denervated, transplanted human heart compared with the acutely auto-denervated of the baboon heart.