Differences in bioavailability between oral cyclosporine formulations in maintenance renal transplant patients.

Previous studies of healthy volunteers and small numbers of transplant recipients have suggested that the oral solution formulation of Sandimmune (cyclosporine [CsA]; Sandoz Pharmaceuticals, East Hanover, NJ) is bioequivalent to the soft gelatin capsule (SGC) formulation. However, there is conflicting evidence as to whether the two formulations are bioequivalent in all patients; to date, there are no published studies that explicitly address their bioequivalence in patients. We conducted a randomized, open-label, two-sequence, two-period, crossover study. Of 20 maintenance renal transplant recipients shown by a screening pharmacokinetic (PK) profile to be poor absorbers of CsA, half were randomized to receive first the SGC formulation and half the oral solution formulation for a period of 7 days. Each patient then underwent a 12-hour PK profile on the last day of the assigned formulation before a crossover to receive the other formulation and repeat the 7-day treatment and PK profile cycle. The results showed that peak and total exposure to CsA was greater with the SGC formulation. The SGC-oral solution ratios indicated an average 38% greater peak and 11% greater total exposure for the SGC formulation (P < 0.01 and P = 0.09, respectively). Trough levels were more similar between formulations, with SGC showing an average of 5% greater troughs (P > 0.10). In our selected population of malabsorbers, the SGC formulation made a difference in drug exposure.

Comparison of arcuate-legged clipped versus sutured hepatic artery, portal vein, and bile duct anastomoses.

Attempts at improving anastomoses have included the development of stapling techniques. Our purpose was to evaluate arcuate-legged clipped versus standard sutured anastomoses of the hepatic artery (HA), portal vein (PV), and bile duct in a porcine liver transplantation model. Two groups of pigs were studied intraoperatively and 1 day after liver transplantation. A control group underwent sutured anastomosis of PV and HA with polypropylene and of bile duct with polydioxanone (n = 8). An experimental group underwent anastomoses with arcuate-legged clips (n = 8). We analyzed the time to perform anastomosis and flows before and at various time points after anastomosis. In addition, patency and histology of the anastomoses were evaluated 1 day after operation, including a fibrin-thrombosis score, medial injury, and inflammation score. Times to complete HA and PV anastomoses were not different between clipped and sutured groups. However, the time was shorter to complete bile duct anastomosis with clips than with sutures (6.3 +/- 1.1 minutes and 13.3 +/- 2.0 minutes, respectively). Flows through HA anastomoses were not different between groups, but flow through the PV was higher in clipped compared with sutured anastomosis (P = 0.06). Patency was 100 per cent with no leaks for all three anastomoses in both groups. Histologic data were similar between vascular anastomotic groups. Sutured bile duct anastomoses revealed mild smooth muscle injury in 75 per cent whereas clipped bile duct anastomoses displayed no smooth muscle injury. We conclude that arcuate-legged clipped anastomosis represents a viable option to sutured anastomoses of the PV, HA, and bile duct anastomoses. Bile duct anastomoses were completed in less than half the time and with less tissue damage documented histologically.

Experience with neoral versus sandimmune in primary liver transplant recipients.

We compared results using Neoral versus Sandimmune, each in combination with steroid and azathioprine immunosuppression, in primary liver transplantation recipients. There were 15 patients in each group with similar demographic distributions. Intravenous cyclosporine was stopped at 4.3 +/- 1.9 days in the Neoral group vs 7.8 +/- 4.9 days in the Sandimmune group. (P < 0.025). Cyclosporine levels in the first 10 days were higher (mean 306 ng/ml vs 231 ng/ml) in the Neoral group than the Sandimmune group (P < 0.05). The Neoral dose was less than the Sandimmune dose (mean 5.5 ng/kg per day vs 7.9 ng/kg per day) to achieve these levels in that time period (P < 0.05). Two patients (13%) experienced three episodes of biopsy-proven rejection in the Neoral group compared to nine patients (60%) with 12 episodes of rejection in the Sandimmune group (P < 0.025). Incidences of neurological and renal complications were similar between the groups. Infections requiring treatment were also similar. Liver function, renal function, and marrow function, evaluated at days 7, 14, 21, 28, and 2, 4, 6, and 12 months post-transplant, were not different between the groups. In summary, shorter use of intravenous cyclosporine and quicker stabilization of trough cyclosporine levels was achieved with Neoral than with Sandimmune. In the early post-transplant period, higher levels with lower doses were achieved with Neoral than with Sandimmune. In our experience, the incidence of rejection was lower with Neoral than with Sandimmune. There were similar lengths of hospitalization, mortality, adverse events, retransplantation, and similar liver, renal, and marrow function up to 1 year post-transplantation. Because of this experience, we continued to use Neoral in a total of 59 primary liver transplant recipients. We have not used intravenous cyclosporine in the last 44 patients. Follow-up was a mean of 11.4 months, ranging from 1 to 27 months. The incidence of rejection was 24% in these 59 patients compared to our historical experience of 70% using Sandimmune.

Hepatic uptake of amino acids immediately after liver transplantation is well preserved despite altered plasma profiles.

BACKGROUND: The liver is one of the principal organs responsible for the uptake and release of amino acids in the body. The ability of the transplanted liver to clear plasma amino acids is associated with a functioning allograft. However, clinical assessment is limited by the inability to access the portal vein postoperatively. Therefore, using a porcine liver transplant model, we examined (1) the plasma levels of amino acids presented to the new hepatic allograft and (2) the capacity of the new allograft to clear these amino acids from the circulation. MATERIALS AND METHODS: Two groups of commercially bred pigs were studied: a control group (n = 8) underwent laparotomy and a transplanted group (n = 6) underwent orthotopic liver transplantation (LT) using veno-venous bypass. All pigs had catheters placed in the carotid artery and portal and hepatic veins and ultrasonic transit time flow probes placed around the hepatic artery and portal vein. Plasma profiles of 23 amino acids were analyzed by high-pressure liquid chromatography. Hepatic balances of amino acids, using arteriovenous difference techniques coupled with hepatic blood flows, were also analyzed on postoperative day 1. RESULTS: Neither portal vein blood flow (703 +/- 74 ml/min vs 666 +/- 82 ml/min) nor hepatic artery blood flow (322 +/- 43 ml/min vs 209 +/- 59 ml/min) was significantly different between the control and the transplanted groups, respectively. The transplanted group had significantly increased plasma levels of alanine (135 +/- 13 mumol/l vs 382 +/- 72 mumol/l), hydroxyproline (30 +/- 5 mumol/l vs 60 +/- 9 mumol/l), methionine (25 +/- 2 mumol/l vs 55 +/- 10 mumol/l), ornithine (36 +/- 5 mumol/l vs 141 +/- 33 mumol/l), phenylalanine (84 +/- 5 mumol/l vs 120 +/- 12 mumol/l), threonine (75 +/- 9 mumol/l vs 159 +/- 27 mumol/l), and tryptophan (17 +/- 2 mumol/l vs 31 +/- 4 mumol/l). The transplanted group also had significantly decreased plasma levels of isoleucine (122 +/- 12 mumol/l vs 85 +/- 8 mumol/l) and taurine (71 +/- 7 mumol/l vs 35 +/- 7 mumol/l). These individual amino acid changes were not accompanied by impairment in the net hepatic amino acid balance or the hepatic fractional extraction of amino acids between the two groups. CONCLUSION: These results suggest that the circumstances associated with liver transplantation alter the fasting amino acid profile immediately postoperatively. However, liver transplantation does not impair the normal hepatic allograft uptake of most plasma amino acids. Thus, the changes observed in the circulating levels of amino acids may represent alterations in nonhepatic production and/or utilization. Furthermore, altered plasma amino acid profiles following liver transplantation are not necessarily indicative of impaired hepatic allograft amino acid metabolism.

Mechanisms of hyperinsulinemia and hyperglucagonemia after liver transplantation.

These studies were undertaken to evaluate the mechanisms for changes in plasma insulin and glucagon levels observed post-liver transplantation. Two groups of pigs were studied: a control group (n = 8) underwent laparotomy and catheter placement in the carotid artery and portal and hepatic veins. Hepatic blood flow was measured by ultrasonic flow probes placed around the hepatic artery and portal vein. An experimental group (n = 8) underwent orthotopic liver transplantation and similar instrumentation. On Day 1 after surgery, an estimate of insulin and glucagon secretion and hepatic extraction was determined using arteriovenous difference techniques. Serum assays were performed for markers of hepatic and renal function. Plasma insulin levels of the transplanted pigs were higher in the carotid artery (4 +/- 1 microU/ml vs 7 +/- 1 microU/ml), but not in the hepatic vein (5 +/- 1 microU/ml vs 7 +/- 1 microU/ml) and in the portal vein (10 +/- 2 microU/ml vs 12 +/- 2 microU/ml). Arterial plasma C-peptide was significantly greater in the transplanted group (0.23 +/- 0.02 ng/ml vs 0.42 +/- 0.03 ng/ml); however, the molar ratio of C-peptide and insulin was not different between the two groups (3.6 +/- 0.9 vs 3.4 +/- 0.4). Plasma glucagon levels of the transplanted pigs were significantly elevated in the carotid artery (111 +/- 11 pg/ml vs 323 +/- 65 pg/ml), portal vein (221 +/- 27 pg/ml vs 495 +/- 69 pg/ml), and hepatic vein (142 +/- 15 pg/ml vs 395 +/- 58 pg/ml). The estimate of pancreatic secretion of insulin (115 +/- 28 microU/kg.min) vs 71 +/- 21 microU/kg.min) and glucagon (2.0 +/- 0.4 ng/kg.min vs 2.7 +/- 0.7 ng/kg.min) and the fractional hepatic extraction rate of insulin (35 +/- 8% vs 32 +/- 5%) were not different between the two groups. However, the hepatic fractional extraction rate of glucagon was significantly decreased in the transplanted group (25 +/- 5% vs 11 +/- 3%). Therefore, the hyperglucagonemia observed 24 hr following liver transplantation is partly due to reduced hepatic fractional extraction of glucagon while the hyperinsulinemia is mainly due to the nonhepatic clearance of insulin. We speculate that decreased renal function may contribute to the hyperinsulinemia, elevated C-peptide concentrations, and hyperglucagonemia.

Outcomes analysis for 50 liver transplant recipients: the Vanderbilt experience.

Healthcare reform has mandated scrutiny of the fiscal aspects of patient care as well as medical outcomes. Therefore, we reviewed our experience with 50 liver transplant recipients from a multidisciplinary collaborative transplant team. From February 1991 to July 1994, of 175 patients referred, 75 were formally evaluated for transplantation; 56 (76%) of these patients were accepted for transplantation; 50 patients underwent 53 transplants. Operative mortality of 6 per cent, retransplantation rate of 6 per cent, 6-month actuarial survival of 88 per cent, 1-year survival of 86 per cent, and the 2 and 3-year survival of 83 per cent were unchanged over time. Quality of life evaluated by the Karnofsky Performance Status was a mean of 55 pretransplant, 72 at 3 months, 79 at 6 months, 84 at 1 year, 88 at 2 years, and 95 at 3 years, demonstrating improved general health and functional rehabilitation after transplantation. Psychosocial Adjustment to Illness Scale scores demonstrated significant improvement following transplantation, improving most dramatically in the vocation environment, domestic environment, and sexual relationship domains. Postoperative length of stay has declined with an average of 28 days in 1991, 22 days in 1992, 19 days in 1993, and 14 days in 1994. Average total hospital, organ procurement, and physician charges for the transplantation hospitalization was $165,000. Average 91-92 hospital charges were $154,000 and were reduced in 93-95 to $103,000 (P < .05). We found that charges and length of stay decreased over time, while the outcome and quality of patient care was maintained. We believe the collaborative practice, case management, and revised patient care protocols are responsible.

Long-term efficacy and safety of cyclosporine in renal-transplant recipients.

BACKGROUND AND METHODS: The safety of long-term immunosuppression with cyclosporine in renal-transplant recipients is not well understood. This drug may cause a progressive toxic nephropathy, but it also preserves renal function because it prevents rejection. To determine the effect of cyclosporine on renal function and graft rejection, we conducted a retrospective analysis of data on 1663 renal-transplant recipients at six centers. RESULTS: The rate of graft survival was 78 percent (median follow-up, 36 months). Grafts were was lost in 279 patients (17 percent), mostly because of acute rejection (68 patients) or chronic graft dysfunction that was unresponsive to a reduction in the dose of cyclosporine (125 patients); 92 patients died with functioning grafts. The median change in the serum creatinine concentration in all patients after transplantation was less than 0.001 mg per deciliter per month (< 0.09 mumol per liter per month). Patients who had episodes of rejection had decreased rates of long-term graft function and survival. Eight percent of patients with functioning grafts at one year had first episodes of rejection more than one year after transplantation. These late first rejections were associated with noncompliance with therapy (in 34 percent), blood cyclosporine concentrations that were marginally lower than those of patients who had no episodes of rejection, and a low rate of successful reversal of rejection (77 percent, vs. 97 percent in patients with rejection during the first year; P < 0.001). CONCLUSIONS: The majority of renal-transplant patients tolerate long-term cyclosporine therapy without evidence of progressive toxic nephropathy. Graft failure is most often due to rejection.

Disseminated histoplasmosis presenting as urinary tract obstruction in a renal transplant recipient.

Disseminated histoplasmosis occasionally involves the kidney, but the infection usually does not cause either urinary symptoms or a decrease in renal function. We present a case of disseminated histoplasmosis in a renal transplant recipient who presented with urinary obstruction in the allograft from a sloughed renal papilla infected with the fungus. At the same time the patient had chronic meningitis from Histoplasma capsulatum. The literature on renal involvement with histoplasmosis is reviewed.

Renal function in patients receiving long-term cyclosporine therapy.

The site at which the vasomotor effects of cyclosporine are associated with acute nephrotoxicity appears to be the afferent arteriole. Proposed mechanisms mediating these effects include sympathetic nerve stimulation, disruption of the balance between vasodilating and vasoconstricting prostaglandins, hypersensitivity to vasoactive peptides, and endothelin release. These mechanisms mediate cyclosporine-associated intrarenal vasoconstriction, yet the causal relationship between these changes and the obliterative vasculopathy seen in association with chronic progressive renal allograft dysfunction is uncertain. Histologic findings seen in chronic progressive renal dysfunction are nonspecific and cannot be correlated solely with cyclosporine use. Retrospective studies analyzing both aggregate serial serum creatinine and reciprocal creatinine determinations did not report a pattern of progressive attrition consequent to toxic nephropathy. Prospective studies with serial GFR determinations with various reference substances found no progressive deterioration in allograft function. Both the retrospective and prospective studies indicate that the attrition of renal allograft function associated with cyclosporine use reflect the chronic effects of immunologic injury. Renal function in extrarenal transplant recipients immunosuppressed with cyclosporine can be characterized by an initial decline in native renal function followed by subsequent stabilization beyond the first 6 months. There does not appear to be an inordinate rate of progression to ESRD.

Chronic immunosuppression of the renal transplant patient.

The advent of potent immunosuppressive drugs to prevent rejection has led to a phenomenal improvement in renal transplant results increasing spectacularly the number of transplant recipients to arrive in the transplant clinic who remain for many years. This has engendered a series of questions about the most appropriate cyclosporine dosing for these patients that prevents rejection while avoiding toxicity. Three separate issues were analyzed: the most appropriate combination strategy with cyclosporine as a base "double" or "triple" therapy; the possibility of conversion from regimens containing cyclosporine to those devoid of it; and the optimal cyclosporine dose for a maintenance regimen. A meta-analysis of seven individual prospective and randomized trials of double versus triple therapy encompassing 1,080 patients revealed no statistical difference between the two regimens in terms of graft survival at 1 or 5 yr, patient survival, the rejection rate per patient, or the infection rate. In an analysis of 17 separate studies in which conversion away from cyclosporine was attempted, in 629 individuals with 702 individuals left on cyclosporine as controls, a significant risk of acute rejection (P < 0.001) was found in the withdrawn group without evidence of improved graft survival. Certain factors such as previous rejection, race, and degree of reactivity predicted even more rejection in the withdrawn group. Analyzing six separate studies of renal transplant recipients maintained on cyclosporine for up to 5 yr with renal functional stability, one can conclude that a dose of approximately 4.0 mg/kg per day is optimal. Because of variant pharmacokinetics or concomitant medicines, blood levels can confirm a therapeutic concentration with this target dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma in a transplanted kidney detected with MAG3 scintigraphy.

We report on two cases of infiltrative renal tumor developing in two kidney transplant recipients from a single cadaveric donor source. Interestingly, while this is only the second case of a de novo renal allograft tumor, both were morphologically infiltrative. The fact that both tumors were infiltrative may be secondary to immunosuppression therapy. While computed tomography (CT) evaluation of suspected renal pathology provides excellent anatomical detail, renal transplant recipients are initially evaluated using ultrasound and renal scintigraphy to avoid contrast reagents which could further impair renal function, as well as to reduce the image procedure cost and the patient radiation dose. Unfortunately, infiltrative tumors may be isoechoic on ultrasound, providing a confusing or conflicting report when compared to scintigraphic findings. This case report is significant radiographically because the original neoplasm was initially detected using technetium-99m-labeled mercaptoacetyltriglycine (99mTc-MAG3) scintigraphy and was not appreciated by sonographic studies, even retrospectively. This case demonstrates the usefulness of 99mTc-MAG3 scintigraphy to follow-up evaluations of renal transplants by providing detailed anatomical information as well as functional analysis of the kidney.

The effect of polyimmune gammaglobulin for prophylaxis against reactivation cytomegalovirus infection in kidney and kidney/pancreas transplant recipients.

Cytomegalovirus (CMV) remains the most important infection in the renal transplant recipient. Few data are available that provide guidance for approaches that seek to reduce the reactivation of latent disease after transplantation. To test the efficacy of polyimmune gammaglobulin in kidney and kidney/pancreas transplantation, consenting recipients with serologic evidence of previous CMV disease were randomized to receive i.v. polyimmune gammaglobulin (500 mg/kg) within 3 days of transplant with 250 mg/kg at weeks 1, 2, 4, and 6 or no prophylaxis. Both groups received identical induction and rejection immunosuppressive therapy. Polyimmune gammaglobulin prophylaxis reduced CMV reactivation infections. The incidence of reactivation infections was half in patients receiving Nashville/rabbit antithymocyte serum (N/R-ATS) compared with those receiving monoclonal anti-CD-3 therapy. Patients receiving polyimmune gammaglobulin along with N/R-ATS had an incidence of infection of only 10%. Reactivation infections were twice as common in patients who had primary nonfunction and nearly three times as common in patients with acute rejection. Both risk factors were associated with longer anti-T-cell therapy. Polyimmune gammaglobulin prophylaxis should be considered in transplant patients with previous CMV exposure who will be receiving prolonged anti-T-cell therapy because of acute rejection or primary nonfunction.

Colonic screening prior to renal transplantation and its impact on post-transplant colonic complications.

Colonic complications after renal transplantation are uncommon but have a high mortality rate. Some have recommended colonic screening in patients over 50 years of age prior to transplantation to lessen the impact of colonic diverticular disease. We report our 9-year experience of colonic screening for diverticular disease in potential recipients over the age of 50 and compare these results to the overall colonic complication rate in the same time period. From 1981-1990, 1186 renal transplants in 1019 patients were performed, during which time all potential recipients over the age of 50 yr were required to undergo colon evaluation prior to transplantation. Twenty cases of diverticular disease were found with more than a quarter of the cases in patients with adult polycystic disease. All underwent renal transplantation without a pre-transplant colectomy, and none had post transplant symptomatic colon disease. During that same time period a total of 14 colonic complications requiring surgical intervention were encountered with a mortality rate of 40%. Acute diverticulitis occurred in 5 patients, all of whom were over 50 yr of age, on low-dose immunosuppression, and in most cases it occurred remotely after transplantation. Colonic dysplasia/neoplasia also occurred remotely after transplantation in 2 patients over the age of 50. Cytomegalovirus (CMV) colitis was the next most common complication, accounting for 3 cases. This complication, which occurred in younger patients, was associated with high-dose steroid immunosuppression and had a high mortality rate, in spite of surgical intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

Single-center analysis of impact of immunosuppressive therapy upon renal allograft survival in the black population.

The effect of race upon renal allograft survival is controversial. Between 1981 and 1987, at Vanderbilt University Medical Center, 448 patients (75 black, 373 white) received azathioprine, 3 mg/kg daily; prednisone, 30 mg daily; and intravenous antithymocyte sera, 0.2 mL/kg/day for 14 days, after transplantation. Prednisone doses were decreased gradually to 10 mg daily within 6 months of transplantation. Azathioprine was maintained at doses of 2 to 3 mg/kg/daily; lower doses were administered if significant myelosuppression occurred. One-year graft survival was 72% and 85% among black and white recipients, respectively (P less than .01). Two hundred thirty-six patients have been treated with azathioprine (3 mg/kg initially tapered during the first week to 1.5 to 2 mg/kg); prednisone, 30 mg daily; and cyclosporine, 10 mg/kg per day. Cyclosporine therapy was begun after recipient serum creatinine levels had decreased below 3 mg/dL. Before therapy was initiated and until levels of cyclosporine were maintained between 150 and 200 ng/mL (whole blood), antithymocyte serum was administered. This immunosuppressive protocol resulted in 1-year graft survival of 90% and 87% in black and white recipients, respectively. Not only was graft loss markedly reduced, but the interracial difference noted before the use of cyclosporine was no longer evident. The type of immunosuppressive therapy used clearly affected 1-year allograft survival among black recipients. The combination of azathioprine, cyclosporine, and prednisone resulted in improved graft survival overall, but had the most significant effect among blacks.