John S. Radomski

Adult human endothelial cell compatibility with prosthetic graft material

We have developed a system for the in vitro evaluation of the interaction of human adult endothelial cells (HAEC) with prosthetic vascular graft material. HAEC, isolated from adult human iliac veins, proliferated vigorously in culture for approximately 70 population doublings. The large number of HAECs produced permitted high-density seeding of prosthetic grafts. Samples of prosthetic material were immobilized on a plastic ring and were used either untreated or coated with extracellular matrix, fibronectin, or plasma. HAEC were seeded at high density and adherence was evaluated by light and electron microscopy after a 2-hr incubation. While essentially no HAEC adhered to untreated grafts, treatment of grafts with either extracellular matrix, plasma, or fibronectin resulted in dramatic adherence of HAEC. The highest density of HAEC adherence was observed on collagen-coated Dacron grafts, and was equal to the cell density observed in confluent monolayers of HAEC grown on gelatin-coated tissue culture plastic. This study demonstrates a method capable of determining HAEC-graft biocompatibility prior to the use of an in vivo system.

Initial adherence of human capillary endothelial cells to dacron

Successful endothelialization of vascular grafts by seeding with endothelial cells (EC) at implantation is related to the number of EC which initially adhere to the graft. Using an in vitro system we examined the initial adherence of EC from human perinephric fat capillaries to woven Dacron that was either unmodified or precoated with several substrates. We studied capillary EC because they have not been investigated as a source of EC for graft seeding, although transinterstitial capillary ingrowth is one possible mechanism for spontaneous graft endothelialization. EC were isolated using collagenase and characterized morphologically and functionally including positive factor VIII-related antigen staining. EC were studied at three phases in culture: (A) primary EC with no subcultivations (EC-0); (B) EC after two subcultivations with trypsin (EC-2); and (C) EC after 10 subcultivations with trypsin (EC-10). EC were seeded onto graft material at a density of 10(5) cells/cm2 (100% confluence) and examined for cell counts and morphology after one day in culture by light and electron microscopy. Results are as follows: (table; see text) The conclusions are: (1) All capillary EC demonstrated adherence to Dacron, but this initial adherence was strongly influenced by graft pretreatment with collagen or plasma. (2) Serially subcultivated EC (EC-2 and EC-10) had significantly higher initial adherence to pretreated Dacron compared to the primary cells (EC-0) (P less than .05). This suggests that briefly cultured and subcultivated EC have superior initial adherence characteristics to treated dacron compared to primary EC with no subcultivations. (3) Fat capillary EC are easily procured and cultured and provide a rich source of human EC for endothelializing vascular prostheses.

Use of an endothelial monolayer on a vascular graft prior to implantation: temporal dynamics and compatibility with the operating room

The temporal sequence of events was examined from initial contact of endothelial cells (ECs) to Dacron until the establishment of a monolayer. Cultured human adult ECs were radiolabeled, seeded onto Dacron, and adherence was quantified after vigorous washing. Firm adherence of 70% of the seeded ECs was seen by 2 hours to untreated Dacron, by 30 minutes to Dacron pretreated with a combination of interstitial type I/III collagen and an amnion-derived basement membrane (Type IV) collagen surface, and by 10 minutes to plasma-coated Dacron. Parallel samples were examined morphologically by scanning electron microscopy (SEM) to evaluate the adherence of ECs to surfaces. ECs seeded onto plain Dacron exhibited limited adherence, while cells on plasma-treated Dacron exhibited limited cell-cell associations. On basement membrane-treated Dacron, by 30 minutes the ECs exhibited a flat attenuated morphology, completely covering the graft surface. This time-frame is compatible with most vascular procedures, making an immediately endothelialized graft feasible.

Pregnancy outcomes in female renal transplant recipients

IN THE PRESENCE of adequate, stable graft function, pregnancies in female renal transplant recipients, although high risk, are generally well tolerated. Although pregnancy may occasionally and unpredictably cause an irreversible decline in renal graft function, the consensus is that pregnancy has no adverse effect on graft function or graft survival. The National Transplantation Pregnancy Registry (NTPR) maintains an ongoing database to study the outcomes of pregnancy in female transplant recipients and pregnancies fathered by male transplant recipients. Previously, we reported that deterioration in recipient graft function during pregnancy is associated with lower newborn birthweights and lower maternal graft survival in cyclosporine (CsA, Sandimmune)-treated renal recipients. The purpose of this study was to identify variables affecting postpartum graft loss in female renal recipients.

Factors associated with severe intracranial hypertension in candidates for emergency liver transplantation

Cerebral edema is the leading cause of death in patients with fulminant hepatic failure (FHF). Emergency OLT is often a life-saving therapy for FHF but severe cerebral edema is a contraindication to transplantation. We attempted to identify clinical and biochemical factors associated with the development of severe intracranial hypertension in FHF. Fever, psychomotor agitation, and arterial hypertension were more frequently observed preceding episodes of severe intracranial hypertension, and more than 50% of FHF patients with uncontrolled intracranial hypertension sustained severe brain injury in our series. These observations suggest that vigorous treatment of fever, arterial hypertension, and agitation are important aspects of the intensive care management of FHF patients to maintain their OLT candidacy.

Surgical management of severe liver trauma: a role for liver transplantation

Severe devascularizing liver injuries continue to carry a high mortality. Rapid operative intervention to achieve hemostasis and debride devitalized tissue remains essential to salvaging these patients. For those with unsalvageable liver injuries liver transplantation can be employed. Careful support of the patient in the anhepatic state, reversal of coagulopathy, and use of venous bypass intraoperatively permit successful transplantation.

Effects of in vitro aging on human endothelial cell adherence to Dacron vascular graft material

The adherence and growth characteristics of cultured human adult large vessel endothelial cells (EC) maintained on substrate-coated polyethylene terephthalate in the form of woven dacron vascular graft were examined. Two different populations of EC, a low passage (EC (low] and a high passage (EC (high] population, were incubated at cell densities from 10(3) to 10(5) EC/cm2 for 24 hr. Cell counts were performed at 24 hr and after 14 days in tissue culture. At 24 hr on collagen I/III-coated Dacron, EC adherence was independent of the number of passages or the incubation density. When examined after 14 days in culture only EC (low) incubated at 10(5) EC/cm2 maintained initial cell numbers. Human plasma precipitated upon Dacron was necessary before significant cell growth occurred. We conclude that increasing in vitro EC age is associated with decreasing attachment and growth on Dacron. Growth on this important vascular replacement surface requires low passage EC incubated at a high density and the presence of plasma proteins in the substrate coating.

28 Results of liver transplantation for nodular regenerative hyperplasia

Liver transplantation has been performed in individuals with a pretransplant clinical diagnosis of cirrhosis but with nodular regenerative hyperplasia histologically. The purpose of this report is to investigate the results of liver transplantation in patients proven to have nodular regenerative hyperplasia post-transplant. A retrospective review was undertaken of four patients who underwent liver transplantation with a histologic diagnosis of nodular regenerative hyperplasia. All were felt to be cirrhotic on clinical grounds. Final histology of the explanted liver was confirmed by a single pathologist. Their ages ranged from 39 to 54 years, and three of the four were male. Three had pretransplant needle liver biopsies, two percutaneous and one transjugular. All revealed nonspecific reactive changes. Ultrasound and MRI were interpreted as consistent with cirrhosis in four of four and three of four cases, respectively. Portal vein flow was hepatopedal in three and absent in one. Pretransplant clinical characteristics and frequency were as follows: bleeding varices two, clinical ascites three, encephalopathy three, and impaired hepatic synthetic function two. All four patients underwent successful liver transplantation. There were no episodes of acute rejection. All are alive and well with normal graft function 2 to 4 years post-transplant. We conclude the following. 1) Patients with clinical end-stage liver disease due to underlying nodular regenerative hyperplasia can successfully undergo transplantation. 2) Nodular regenerative hyperplasia can present with signs and symptoms of liver failure, is difficult to diagnose by needle biopsy, and can be difficult to discriminate clinically from cirrhosis. 3) Although each case must be individually evaluated transplantation may be the optimal therapy in patients presenting with complications of liver failure.