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J Rozga

Publications and source records attributed to J Rozga.

At least 37 records · Page 2Linked to original sources
PubMed1997

Treatment of severe liver failure with a bioartificial liver.

Orthotopic liver transplantation (OLT) is the definitive therapy for severe liver failure. However, many patients die before an organ becomes available, mostly from cerebral edema. To provide temporary liver support, we developed a bioartificial liver (BAL) based on porcine hepatocytes and a charcoal column. Fifty-four consecutive BAL treatments were carried out in three groups of patients: Group I (n = 15) patients presented with FHF were listed for emergent OLT, Group II (n = 3) patients with primary non-function (PNF) of their liver grafts required urgent re-transplantation and Group III (n = 10) patients with acute exacerbation of chronic liver disease were not candidates for OLT. Patients were managed in a critical care unit receiving maximal standard support. Each BAL treatment was conducted for 6 hours. In Group I, all patients showed significant neurologic improvement, intracranial pressure (ICP) decreased and cerebral perfusion pressure (CPP) increased; other significant improvements, included lowered plasma ammonia and liver enzymes and increased glucose. One patient recovered spontaneously without OLT, all other patients were "bridged" to OLT, and recovered. Group II: PNF patients showed similar benefits. Group III: Chronic liver patients demonstrated transient beneficial effects after BAL treatment(s), however, most (n = 8) eventually succumbed to sepsis and multiple organ failure as they were not candidates for OLT; two patients, recovered, later were successfully transplanted and survived. Our clinical experience demonstrates that the BAL can serve as a bridge to OLT in patients with acute liver failure.

Adult↗
PubMed1997

Fetal rat hepatocytes: isolation, characterization, and transplantation in the Nagase analbuminemic rats.

BACKGROUND: In contrast to adult hepatocytes, fetal hepatocytes (FH) are thought to be highly proliferative, less immunogenic, and resistant to cryopreservation and ischemic injury. These qualities could enhance FH engraftment, proliferation, and gene transfer requiring active DNA synthesis. METHODS: Rat FH were obtained using the nonperfusion collagenase/DNase digestion method. Free and cultured cells were studied using electron microscopy, fluorescence-activated cell sorting, and Northern analysis using alpha-fetoprotein and albumin as markers of hepatocyte lineage. DNA synthetic activity was measured in quiescent and mitogen-stimulated fetal and adult hepatocytes by [3H]thymidine incorporation. Susceptibility of cultured FH to retrovirally mediated gene transfer was studied using an amphotropic retroviral vector carrying the Escherichia coli lac-Z gene. Nagase analbuminemic rats were used as recipients to study the effects of intraportal FH transplantation. Analysis of serum albumin was carried out by enzyme-linked immunosorbent assay. RESULTS: In fetal liver, 87+/-2% of the cells showed morphological and molecular features of hepatocytes. DNA synthetic activity in nonstimulated cultured FH was 10 times greater than the maximal hepatocyte growth factor-driven response in adult rat hepatocytes. A total of 5-15% FH stained positive for X-gal; results of transduction in adult hepatocyte cultures were negative. In Nagase analbuminemic rat recipients, FH produced significant amounts of albumin only when a hepatic regenerative stimulus was applied. Immunohistochemistry confirmed presence of albumin-positive hepatocytes. CONCLUSIONS: Fetal rat liver from the late gestation period is highly enriched with hepatocyte progenitors. They are highly proliferative and susceptible to retroviral transduction and can engraft and function in the adult rat liver if transplanted under a hepatic regenerative stimulus.

Acetylglucosaminidase↗
PubMed1997

Loss and recovery of liver regeneration in rats with fulminant hepatic failure.

We earlier described a model of fulminant hepatic failure (FHF) in the rat where partial hepatectomy is combined with induction of right liver lobes necrosis. After this procedure, lack of regenerative response in the residual viable liver tissue (omental lobes) was associated with elevated plasma hepatocyte growth factor (HGF) and transforming growth factor beta (TGF-beta1) levels and delayed expression of HGF and c-met mRNA in the remnant liver. Here, we investigated whether syngeneic isolated hepatocytes transplanted in the spleen will prolong survival and facilitate liver regeneration in FHF rats. Inbred male Lewis rats were used. Group I rats (n = 46) received intrasplenic injection of 2 x 10(7) hepatocytes and 2 days later FHF was induced. Group II FHF rats (n = 46) received intrasplenic injection of saline. Rats undergoing partial hepatectomy of 68% (PH; n = 30) and a sham operation (SO; n = 30) served as controls. In 20 FHF rats (10 rats/group), survival time was determined. The remaining 72 FHF rats (36 rats/group) were used for physiologic studies (liver function and regeneration and plasma growth factor levels). In Group I rats survival was longer than that of Group II controls (73 +/- 22 hr vs. 33 +/- 9 hr; P < 0. 01). During the first 36 hr, Group I rats had lower blood ammonia, lactate, total bilirubin, PT, and PTT values, lower activity of liver enzymes, and higher monoethylglycinexylidide (MEGX) production than Group II rats. In Group I rats, livers increased in weight at a rate similar to that seen in PH controls and showed distinct mitotic and DNA synthetic activity (incorporation of bromodeoxyuridine and proliferation cell nuclear antigen expression). Plasma HGF and TGF-beta1 levels in these rats decreased and followed the pattern seen in PH rats; additionally, c-met expression in the remnant liver was accelerated. Hepatocyte transplantation prolonged survival in FHF rats and facilitated liver regeneration. Even though the remnant liver increased in weight four times reaching 30% of the original liver mass, the transplant-bearing rats expired due to inability of the regenerating liver to support the rat.

Albumins↗
PubMed1997

Clinical experience with a bioartificial liver in the treatment of severe liver failure. A phase I clinical trial.

OBJECTIVE: The purpose of this study was to develop a bioartificial liver (BAL) to treat patients with severe liver failure until they can be either transplanted or recover spontaneously. SUMMARY BACKGROUND DATA: Severe acute liver failure is associated with high mortality. Liver transplantation has emerged as an effective therapy for patients who did not respond to standard management. However, because of the donor organ shortage and urgent need for transplantation, many patients die before they can be transplanted and others do not survive after transplantation, primarily because of intracranial hypertension. METHODS: Three groups of patients with severe acute liver failure were treated with the BAL. In group 1 (n = 18) were patients with fulminant hepatic failure (FHF), in group 2 (n = 3) were patients with primary nonfunction (PNF) of a transplanted liver, and in group 3 (n = 10) were patients with acute exacerbation of chronic liver disease. Patients in groups 1 and 2 were candidates for transplantation at the time they entered the study, whereas patients in group 3 were not. RESULTS: In group 1, 16 patients were "bridged" successfully to transplantation, 1 patient was bridged to recovery without a transplant, and 1 patient died because of concomitant severe pancreatitis. In group 2, all patients were bridged successfully to retransplantation. In group 3, two patients were supported to recovery and successful transplants at later dates; the other eight patients, although supported temporarily with the BAL, later died because they were not candidates for transplantation. CONCLUSIONS: The authors' clinical experience with the BAL has yielded encouraging results. A randomized, controlled, prospective trial (phase II-III) is being initiated to determine the efficacy of the system.

Adult↗
PubMed1996

Treatment of hypercholesterolemia in the Watanabe rabbit using allogeneic hepatocellular transplantation under a regeneration stimulus.

Numerous studies have reported successful allotransplantation of hepatocytes. However, none have shown long-term correction of a liver-related metabolic defect. In this study, we used a method of regional hepatocyte transplantation and subsequent induction of transplanted cell proliferation by regeneration response in the transplant-bearing liver lobes. New Zealand White rabbits were used as cell donors and Watanabe heritable hyperlipidemic (WHHL) rabbits were used as cell recipients (2 x 10(8) cells/rabbit). All recipient rabbits were maintained on daily cyclosporine. Two weeks after baseline serum cholesterol determination, group I WHHL rabbits (n = 7) received an infusion of cells into the right lateral liver lobe, and a loose ligature was placed around the portal venous branch supplying the anterior lobe. After 1 week, to allow engraftment, the portal venous branch was ligated, which resulted in the atrophy of the affected liver parenchyma and induction of hyperplasia in the transplant-bearing liver tissue. Group II rabbits (n = 6) were transplanted with New Zealand White hepatocytes without portal branch ligation (PBL) and group III rabbits (n = 4) were subjected to sham transplantation (saline) and PBL. The experimental period extended to 150 days after transplantation. All WHHL rabbits transplanted with normal hepatocytes showed reduction in serum cholesterol and low-density lipoprotein (LDL) levels. Group I (PBL-stimulated) recipients demonstrated a more pronounced and sustained effect than group II animals (P < 0.05). Group III controls showed only a slight, typical for aging decrease in serum cholesterol. Group I recipient livers perfused with LDL labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate (DiI) showed much higher numbers of DiI-LDL-positive hepatocytes than those of group II recipients. In conclusion, a liver regeneration stimulus enhanced the population of transplanted hepatocytes and their functional effect in a large animal model of inborn error of liver metabolism.

Alanine Transaminase↗
PubMed1996

Fulminant hepatic failure in rats: survival and effect on blood chemistry and liver regeneration.

A reproducible experimental animal model of fulminant hepatic failure (FHF) resembling the clinical condition is needed. We have developed such a model in the rat by combining resection of the two anterior liver lobes (68% liver mass) with ligation of the right lobes pedicle (24% liver mass), resulting in liver necrosis; the remaining two omental lobes (8% liver mass) are left intact. Adult Sprague-Dawley rats (250-300 g) were used. Survival time was determined in 60 rats. Because maintenance of body temperature at 37 degrees C shortened survival time by half, FHF rats were not warmed during the postinduction period and were allowed to gradually enter a state of mild to moderate hypothermia (29-32 degrees C). Additionally, 42 FHF rats were killed in batches of six rats each 2, 6, 12, 18, 24, 30, and 36 hours postoperatively to evaluate changes in blood chemistry (glucose, lactate, liver function tests, prothrombin time) and to assess liver regenerative response in the residual omental liver lobes (weight, protein content, incorporation of bromodeoxyuridine [BrdU], expression of proliferation cell nuclear antigen [PCNA], mitotic activity), plasma levels of hepatocyte growth factor (HGF) and transforming growth factor beta (TGF-beta1), and tissue expression of the HGF and it's receptor c-met. Rats undergoing partial hepatectomy of 68% (PH; n = 42) and a sham operation (SO; n = 42) served as controls. All SO and PH controls survived. PH rats showed only transient decreases in body temperature, signs of modest early hepatic dysfunction (hyperlactemia, hyperammonemia, prolonged PT time), and normal restitution of liver mass. All FHF rats became comatose by 24 hours postoperatively. Most animals (90%) died within 24-48 hours postoperatively (mean, 39 +/- 11 hours). Changes in blood chemistry reflected rapid development of liver failure. Plasma HGF levels were markedly elevated and at all time points were higher than in PH controls (P < .05). At the same time, expression of HGF and c-met messenger RNA in the remnant liver was delayed. Plasma TGF-beta1 levels increased early (18 hours) and remained twofold to threefold higher than that of PH and SO controls (P < .05). There was only a 20% increase in the weight of the remnant liver lobes due to swelling. No hepatocytes stained positively for BrdU and PCNA, and none showed mitotic figures. In contrast, all PH controls showed vigorous liver regeneration. In conclusion, we have developed and characterized a novel model of FHF in rats that has a number of physiological and biochemical features seen clinically in FHF, including severely impaired ability of the residual liver tissue to regenerate.

Animals↗
PubMed1996

Techniques for intrasplenic hepatocyte transplantation in the large animal model.

BACKGROUND: The preferred therapy for acute and chronic liver insufficiency and severe heritable disorders of liver metabolism is whole-organ transplantation. However, due to the shortage of organ donors and high cost, alternative therapeutic approaches have been proposed, including transplantation of normal allogeneic hepatocytes. Recently, it has been reported that many hepatocytes transplanted into the spleen migrated to the liver. We therefore carried out a series of large-animal experiments to reexamine the intrasplenic route and to develop a method for large-scale hepatocellular transplantation in pigs. METHODS: Allogeneic porcine hepatocytes were transplanted using the following routes: (1) retrograde injection of cells via the splenic vein, (2) intraarterial injection of cells, (3) direct intrasplenic injection of cells after laparotomy, (4) percutaneous intrasplenic injection of cells under laparoscopic control, (5) laparoscopic intrasplenic injection of cells. The number of cells injected varied from 2 x 10(9) to 10 x 10(9) cells. RESULTS: Of all the methods tested, only direct intrasplenic injection of 2 bln of cells was found to be compatible with survival. However, even with this "small" number of cells (2% original liver mass), there was a significant risk of spleen infarction, perisplenic adhesion formation, and portal vein thrombosis. The laparoscopic approach was found to be reliable, simple, and safe. CONCLUSION: Even though the spleen is considered by many authors the optimal site for hepatocellular transplantation, transplantation of cells in a number needed to support the failing liver may be associated with significant complications, morbidity, and mortality.

Animals↗
PubMed1996

Matrix-induced liver cell aggregates (MILCA) for bioartificial liver use.

Ex vivo reproduction of liver microstructure using isolated hepatocytes is critical for bioartificial liver use. We have developed a method of producing matrix-induced liver cell aggregates (MILCA) using a small number of collagen-coated beads as a nidus for formation of hepatocyte aggregates. Porcine hepatocytes were obtained by EDTA/collagenase digestion. Cell viability was assessed by trypan blue exclusion and LDH release. Cytochrome P-450 activity was determined at 4 and 24 hours by measuring the formation of 7-hydroxycoumarine (7-HC) from 7-ethoxycoumarine (7-EC). At 4 hours, the viability of MILCA was 92 +/- 2%, LDH release was 100 +/- 22 U/L and 7-HC formation was 140 +/- 34 nM/g cells. At 24 hours, MILCA viability remained greater than 90%, but 7-HC formation was lower than that of parallel control monolayer hepatocyte cultures (194 +/- 43 vs 481 +/- 78 nM/g cells; p < 0.002). On transmission electron microscopy, MILCA ultrastructure resembled that of a normal liver (maintenance of cell polarity, gap junctions, bile canaliculi, intact organellae, glycogen granules). MILCA were subsequently inoculated into hollow-fiber bioreactors which were perfused for 6 hours with plasma recovered from patients with fulminant hepatic failure (n = 6; 5 x 10(9) cells/cartridge, recirculation of 350 ml of plasma at 400 ml/min). In these studies, lidocaine (20 micrograms/ml) was cleared in less than 3 hours and 7-HC production at 6 hours was 71 +/- 8 nM/g cells. Other MILCA effects noted in this system included lowering of plasma lactate, bilirubin and ammonia and increase in the level of several non-essential amino acids.

Alginates↗
PubMed1996

Clinical experience with a porcine hepatocyte-based liver support system.

UNLABELLED: The only clinically proven effective treatment of fulminant hepatic failure (FHF) is orthotopic liver transplant (OLT). However, many patients die before an organ becomes available. Thus, there is a need for development of an extracorporeal liver support system to "bridge" these patients either to OLT or spontaneous recovery. We developed a bioartificial liver (BAL) based on plasma perfusion through a circuit of a hollow-fiber cartridge seeded with matrix-anchored porcine hepatocytes to treat patients with severe acute liver failure. Two groups of patients were studied. Group 1 (n = 12): patients with FHF. All patients were successfully "bridged" to OLT. "Bridge" time to OLT was 21-96 hr (mean: 39.3 hr). All patients were discharged neurologically intact. Reversal of decerebration was noted in all 11 deep stage 4 coma patients. There was reduction in intracranial pressure (ICP mmHg, 18.2 +/- 2.2 to 8.5 +/- 1.2; p < 0.004) and increase in cerebral perfusion pressure (CPP mmHg, 71.1 +/- 4.0 to 84.7 +/- 2.6; p < 0.006). Laboratory values pre- and post-BAL treatment: glucose (mg/dl) 122 +/- 11 to 183 +/- 21, p < 0.002; ammonia (mumol/l) 155.6 +/- 13.2 to 121.6 +/- 9.5, p < 0.02; total bilirubin (mg/dl) 21.6 +/- 2.8 to 18.2 +/- 2.2, p < 0.001; PT (sec) 23.2 +/- 1.7 to 21.9 +/- 1.0, p < 0.3. Group II (n = 8): patients with chronic liver failure experiencing acute exacerbation. Two patients survived and later underwent OLT. Six patients (not OLT candidates) died 1-14 days after last BAL treatment. Laboratory values pre- and post-treatment: ammonia (mumol/l) 201 +/- 47 to 143 +/- 25, p < 0.06; total bilirubin (mg/dl) 22.8 +/- 5.2 to 19.5 +/- 4.4, p < 0.01; PT (sec) 22.5 +/- 2.0 to 21.8 +/- 1.1, p < 0.6. CONCLUSION: our clinical experience with the BAL suggests that it may serve as "bridge" to OLT in patients with FHF primarily by reversing intracranial hypertension, but it is not a substitute for OLT in patients with end-stage liver disease who are non-transplant candidates.

Adolescent↗
PubMed1995

Plasma separation for artificial liver support.

A bioartificial liver (BAL) support system, using plasma separation, has been developed to support acute liver failure patients. This study examined 14 consecutive BAL treatments in nine patients with severe acute liver failure. We report methods to achieve and manage plasma separation for an extended period of time. The mean duration of a BAL treatment was 435 minutes, with 26-59 liters of blood processed. Ionized hypocalcemia resulting in muscle twitching was a side effect of the therapy. Ionized calcium levels decreased significantly (P < .02) after BAL treatment; however, total calcium levels increased (P < .05). No significant changes were noted in heart rate, electrocardiogram [Q-T (Q-Tc) interval], blood pressure, prothrombin time, partial thromboplastin time, hematocrit, platelet count and serum phosphorous, magnesium, glucose, and pH. Plasma fibrinogen levels decreased significantly (P < .002). Ionized hypocalcemia due to the chelating effect of sodium citrate was controlled by calcium chloride administration, adjustment of blood separation rates, and reduction of the blood-to-citrate ratio. This report demonstrates that intensive, large-volume plasma separation for long periods of time can be achieved safely in critically ill patients without serious adverse effects.

Adolescent↗
PubMed1995

Differential patterns of reaction of human natural antibodies to pig hepatocytes and vascular endothelium.

We have recently conducted a series of experiments to characterize the pattern of reaction of human natural antibodies (NA) with individual pig liver cells. Pooled normal human serum (PHS) was incubated with cultured pig hepatocytes (HEP), aortic endothelial cells (AEC), and portal endothelial cells (PEC), and the reaction of NA to different cell types was measured by antibody-mediated cytotoxic (MTT assay), antibody binding (ELISA), and flow cytometric analysis. The human NA displayed a differential pattern of binding with hepatocytes exhibiting a more limited expression of xenoantigen expression than either aortic or portal endothelial cells. These differences in reaction patterns were also noted for Western blot analysis of individual cell membrane extracts. Preincubation of the pig cells with anti-pig MHC antibodies did not inhibit the binding of human IgM natural antibodies to the pig cells. Comparison of the pattern of NA absorption following the use of bioartificial liver support in patients with acute hepatic failure demonstrated limited ability of pig hepatocytes to absorb substantial amounts of NA. These studies indicate that pig hepatocytes are less vulnerable to NA cytotoxicity than pig vascular endothelial cells and that pig vascular endothelial cells express xenoantigens that are unique and not found on hepatocytes.

Animals↗
PubMed1995

Teleost fish islets: a potential source of endocrine tissue for the treatment of diabetes.

Anatomical separation of pancreatic islets in some teleost fish makes them a useful source of pancreatic endocrine tissue. Islets were harvested from tropical Tilapia fish (Oreochromis nilotica) and cultured for 24 hr at 37 degrees C. Eight athymic nude mice were rendered diabetic by streptozotocin (STZ) and transplanted under the kidney capsule with fish islets. After transplantation (Tx), nonfasting blood glucose (n-FBG), which was in all recipients > 450 mg/dl, decreased to < 100 mg/dl. At 4 and 7 weeks post-Tx, the intraperitoneal (ip) glucose tolerance test was performed in the normoglycemic Tx mice and in six normal controls. In controls, K value (percentage of decline in blood glucose/min) was 1.076 +/- 0.383 and in Tx mice it was 0.956 +/- 0.336 and 0.869 +/- 0.483 at 4 and 7 weeks, respectively (P = n.s.). Nephrectomy raised the n-FBG to pre-Tx levels. On immunohistochemistry, recipient's pancreata showed atrophic islets with no beta-cell granules, while the islet-bearing kidneys had distinct beta-cells under their capsules. Alginate-embedded fish islets were encapsulated in permselective (25-kDa) cellulose membranes and implanted ip in six STZ-diabetic nude mice. On the following day, all recipients became normoglycemic and their n-FBG remained normal for 7 days. In one animal, the n-FBG was < 200 mg/dl for 14 days and subsequent removal of the capsule raised the n-FBG to the pre-Tx level. Finally, it was found that fish islets can be cultured at 37 degrees C for extended periods of time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Early clinical experience with a hybrid bioartificial liver.

BACKGROUND: Severe liver failure is associated with high mortality. Orthotopic liver transplantation (OLT) is the only effective therapeutic modality; there is a need for a 'bridge' system to support patients until an organ becomes available. METHODS: A bioartificial liver (BAL) was used to treat 10 patients with severe liver failure. A plasmapheresis system was used to pump patient plasma through a module with porcine hepatocytes. Each treatment lasted 6-7 h. RESULTS: All patients tolerated the procedure(s) well. Eight patients underwent OLT following BAL treatment(s). There were two late deaths after recovery from liver failure. Five patients with increased intracranial pressure (ICP) and decerebration had ICP normalization, increased cerebral perfusion pressure and full neurologic recovery after OLT. There was improvement in the level of encephalopathy and a significant decrease in serum ammonia after BAL treatment(s). CONCLUSIONS: BAL treatment is safe and beneficial and can be successfully used as a 'bridge' to transplantation.

Adult↗
PubMed1995

Artificial hepatic support systems.

Severe acute liver failure is associated with high mortality. Improved respiratory and hemodynamic management together with intracranial pressure monitoring and aggressive treatment of cerebral edema have greatly improved patient care. However, many patients die despite optimal medical treatment, because of failure to arrest the progression of cerebral edema. This in turn result in brain stem herniation with rapid neurologic deterioration and death. Liver transplantation has emerged as the definitive treatment for patients with severe acute liver failure. Unfortunately approximately up to one half of the patients with this severe form of liver failure will die while awaiting liver transplantation. There is thus a clear need for a liver support system to provide a "bridge" to transplantation. Over the years, many "bridge" systems were introduced which promised effective support but had no wide clinical success. Because of our incomplete understanding of the pathophysiology of liver failure and development of cerebral edema, it was felt that use of isolated hepatocytes or ex vivo whole liver perfusion would provide both detoxifying and synthetic functions. Whole liver perfusion appears to be effective but cumbersome and costly because it would require each center, where patients are being treated, to maintain animal colonies for patient treatment. Therefore, cryopreserved isolated xenogeneic hepatocytes appear to be the best candidates for building a "bridge" system. In a preliminary clinical study, we have used a porcine hepatocyte-based liver support system (Bioartificial Liver: BAL) to treat patients with acute liver failure as well as patients with acute exacerbation of chronic liver disease. Patients in the first group, who were candidates for transplantation, were successfully bridged to a transplant with excellent survival. No obvious benefit from BAL treatments was seen in the second group. In this group patients where cerebral edema is not a major component of the clinical presentation, it is possible that long-term support will be needed with repeated treatments over several weeks to provide adequate synthetic and detoxifying liver function until the patients' livers recover. For such liver recovery to take place, these chronic patients will need to be treated earlier in the course of their disease when they still have some residual liver mass as well as regenerative capacity. Prospective controlled trials will be initiated as soon as the current phase I study is concluded in order to determine the efficacy of this system in both patient populations.

Animals↗