Occurrence of gammopathies and lymphoproliferative disorders in liver transplant recipients randomized to tacrolimus (FK506)- or cyclosporine-based immunosuppression

Lymphoproliferative disorders (LPDs) are a serious side effect of immunosuppression after liver transplantation, and the introduction on the market of a new immunosuppressive drug has been associated with an increased risk of these disorders. To compare the effect of cyclosporine A (CSA) and FK506 in a clinical setting, the incidence of monoclonal or oligoclonal gammopathies known to often precede the appearance of LPDs was evaluated. A total of 88 adult patients was analyzed, 46 were prospectively randomized to CSA and 42 to FK506 for immunosuppression. None of these patients had gammopathy before transplantation. All the patients were tested for immunoglobulin abnormalities five to nine times during a period of 1 year and then two to four times per year thereafter from December 1990 until March 1997. The same incidence of serum immunoglobulin (Ig) abnormalities was observed in both groups (13%) with a mean delay of appearance of 11.1 +/- 5.9 versus 7.6 +/- 3.6 months for CSA and FK506, respectively (P > .05). In each group, the gammopathies were transient in 3 patients and persisted in 2. The class of Ig involved was IgG, and a monoclonal component was documented in 2 patients treated with CSA and in 3 patients with FK506. One patient treated with FK506 developed an LPD localized to the lymph nodes 8 months after the occurrence of serum protein abnormalities. The lymphoproliferative lesions subsequently disappeared with the reduction of immunosuppression. In this study, an immunosuppressive regimen of FK506 has not shown an increased incidence of lymphoproliferation compared with CSA in adult liver transplant patients.

Acute cyclosporine toxicity after liver transplantation is predicted by the lidocaine monoethylglycinexylidide test in the donor

Cyclosporine toxicity is still a significant problem in the early period after liver transplantation. The monoethylglycinexylidide (MEGX) test performed in the donor has been suggested as a reliable test to predict liver graft function in the recipient. The MEGX test was performed in 50 consecutive donors, and the clinical course of recipients, metabolic parameters of the grafts, and cyclosporine levels were followed in detail for 10 days. Two patients died of sepsis and were excluded. Renal and/or neurological toxicity appeared in 15 of the remaining 48 patients (31%). In the 6 with neurological problems, MEGX values were low (41, 47, 50, 60, 94, and 101 micrograms/L). Nine patients had transient elevations of creatinine and urea; in 8 of these, cyclosporine levels remained in the normal range. Low MEGX values in the donors correlated with early evidence of cyclosporine toxicity (P < .0001), reduced graft function (bile output, P = .04; prothrombin time at day 5, P = .005), and prolonged stay in the intensive care (P = .022). The MEGX test is valuable and reflects the metabolic capacity of liver grafts. It can predict posttransplantation complications caused by cyclosporine toxicity, and further study would evaluate its incorporation into immunosuppressive protocols.

Prospective evaluation of circulating hepatocytes by alpha-fetoprotein mRNA in humans during liver surgery

OBJECTIVE

The objective of this study was to analyze the specificity of detecting liver tumor cell dissemination by alpha-fetoprotein (AFP) mRNA in peripheral blood.

SUMMARY BACKGROUND DATA

Alpha-fetoprotein mRNA has been used for the detection of circulating micrometastatic tumor foci of hepatocellular carcinoma (HCC); however, the interpretation of the results has been equivocal.

METHODS

Sixty-four consecutive patients with malignant HCC (n = 20), liver metastases (n = 27), or nonmalignant (n = 17) liver diseases undergoing partial or total hepatectomy and orthotopic liver transplantation were included in this prospective study from January to July 1995. Peripheral blood samples were obtained before surgery, during surgery, and after surgery (range, 6-15 months). Total mRNA was extracted from nucleated cells, and cDNA synthesis and polymerase chain reaction amplification (nested polymerase chain reaction in one tube) were performed with specific AFP primers.

RESULTS

Preoperative AFP mRNA was detected in 20 patients (17%), of which 5 of 20 had HCC. Intraoperative assessment showed positive AFP mRNA values in a total of 34 patients (53%) with various causes, of which 8 of 20 (40%) had HCC, 17 of 27 (63%) had other malignancies, and 9 of 17 (53%) had nonmalignant diseases. Recurrent tumor in patients with HCC occurred in four cases after surgery (range, 6-15 months) and did not correlate with AFP mRNA positivity before surgery, during surgery, or after surgery.

CONCLUSIONS

Alpha-fetoprotein mRNA in peripheral blood is not a specific marker of circulating micrometastases from HCC, especially in the context of surgical treatment of HCC.

A new technique of one-stage total hepatectomy in the rat

BACKGROUND

A small animal model of one-stage total hepatectomy is needed for the study of the consequences of fulminant liver failure and to investigate the extrahepatic metabolism of drugs metabolized by the liver. The models of hepatectomy described previously in the rat have the disadvantage of multiple stages, technical difficulty, or achievement of only an incomplete removal of the liver tissue.

METHODS

A Y-shaped graft was prepared from the inferior vena cava and the left renal vein of a donor rat. A total hepatectomy was performed in a recipient rat. The graft was placed and the portorenal and lower cavocaval anastomoses were performed by means of the polyethylene cuff technique. The upper cavocaval anastomosis was fashioned with a continuous suture. The procedure was performed on 49 rats, and the animals were studied for survival and biochemical profiles.

RESULTS

The surgical procedure took a mean of 40 +/- 5 minutes and was not associated with any operative deaths. The portal clamping time did not exceed 15 minutes. Spontaneous mean survival of the anhepatic rats was 360 +/- 30 minutes, and glucose supplemented animals had a mean survival time of 20 +/- 5 hours. The anhepatic state was associated with significant metabolic and biochemical alterations.

CONCLUSIONS

This procedure is quick to perform and does not require considerable microsurgical expertise. It provides a reproducible small animal model of total hepatectomy that is particularly useful for metabolic studies.

Frequent microsatellite instability in post hepatitis B viral cirrhosis

The molecular basis of cirrhosis, the most frequent underlying liver disease in hepatocellular carcinoma, remains unclear. We investigated microsatellite instability at six different loci on chromosomes 2p, 3p, 5q, 9p, 13q and 17p, in DNA from 38 cirrhotic livers of viral (n=28) and nonviral (n=10) origin. Sixty percent of the patients exhibited microsatellite alterations in at least one chromosome locus. A striking feature was the close association between genomic instability and cirrhosis linked to hepatitis B viral infection (P<0.01). This high instability may be a clue to the etiology of cancer induced by the hepatitis B virus.

Cloning and sequencing of a cDNA encoding a larval-pupal-specific cuticular protein in Tenebrio molitor (Insecta, Coleoptera). Developmental expression and effect of a juvenile hormone analogue

A cDNA clone encoding a larval-pupal cuticular protein, named TMLPCP-22, has been isolated by screening a library in expression vector with a monoclonal antibody made against pupal cuticular proteins of Tenebrio molitor. Northern-blot and in situ hybridization analyses showed that the expression of TMLPCP-22 is regulated in a stage-specific and tissue-specific manner; the transcript was present during the secretion of preecdysial larval and pupal cuticles and was restricted to epidermal cells. No expression was observed during adult cuticle deposition. In supernumerary pupae obtained after application of a juvenile hormone analogue, which is known to inhibit the adult programme, TMLPCP-22 mRNA was expressed again, confirming its larval-pupal specificity.

Nonisotopic competitive RT-PCR assay to measure MDR1 gene expression

We report an original application of competitive reverse transcription-polymerase chain reaction (RT-PCR) for the quantification of MDR1 mRNA in clinical specimens by simultaneous reverse transcription and PCR amplification of cellular RNA with decreasing amounts of an internal standard. The competitor RNA shares the same MDR1 primer sequences as the cellular mRNA, but yields a different-sized PCR product. This allows resolution of the amplified cDNA fragments after agarose gel electrophoresis and ethidium bromide staining. The concentration of MDR1 mRNA is derived from the ratio between the intensities of the bands corresponding to the amplified products. We have used this assay to measure MDR1 expression in breast carcinomas and assessed the precision, sensitivity, and accuracy of the method. Competitive RT-PCR is a simple, highly specific, nonradioactive procedure for the quantification of MDR1 mRNA and is particularly suitable for use in the clinical laboratory.

Nonisotopic competitive RT-PCR assay to measure MDR1 gene expression

We report an original application of competitive reverse transcription-polymerase chain reaction (RT-PCR) for the quantification of MDR1 mRNA in clinical specimens by simultaneous reverse transcription and PCR amplification of cellular RNA with decreasing amounts of an internal standard. The competitor RNA shares the same MDR1 primer sequences as the cellular mRNA, but yields a different-sized PCR product. This allows resolution of the amplified cDNA fragments after agarose gel electrophoresis and ethidium bromide staining. The concentration of MDR1 mRNA is derived from the ratio between the intensities of the bands corresponding to the amplified products. We have used this assay to measure MDR1 expression in breast carcinomas and assessed the precision, sensitivity, and accuracy of the method. Competitive RT-PCR is a simple, highly specific, nonradioactive procedure for the quantification of MDR1 mRNA and is particularly suitable for use in the clinical laboratory.

The effects of donor and recipient endotoxemia on TNF alpha production and mortality in the rat model of syngenic orthotopic liver transplantation

The effects of administration of endotoxin to donors or recipients on the mortality rate, evolution of endotoxin levels, and tumor necrosis factor alpha (TNF-alpha) release were investigated in a syngenic orthotopic liver transplantation model in Lewis rats with portal reperfusion only. No significant recipient endotoxemia, TNF-alpha release, or mortality occurred in control recipients following transplantation from normal donors. The doses of endotoxin needed to kill 50% and 100% of animals after hepatic artery ligation were, respectively, 4 mg/kg and 10 mg/kg. Transplantation of animals' livers with no preservation phase from donors who were administered a lethal dose of endotoxin for this combination (10 mg/kg) produced significant recipient endotoxemia at 10 min (6.9 +/- 2.5 x 10(3) endotoxin unit/ml (EU/ml), P < 0.01), 45 min (8.8 +/- 1.1 x 10(3) EU/ml, P < 0.001) and 8 hr (18.5 +/- 3.5 x 10(3) EU/ml, P < 0.001) after graft reperfusion. Significant levels of TNF-alpha were also detected in these animals at 45 min (280 +/- 70 pg/ml, P < 0.007) and 8 hr (80 +/- 40 pg/ml, P < 0.05) when compared with the controls. Mortalities in recipients of OLT from donor animals that had received endotoxin (2 mg/kg or 4 mg/kg) immediately prior to the harvesting procedure was 0% and 20%, respectively, compared with no death in the control group. When recipient animals were administered endotoxin immediately after graft reperfusion the resistance to endotoxin administration was significantly reduced compared with animals that had not received OLT (LD50 < 2 mg/kg versus 4 mg/kg; LD100 4 mg/kg versus 10 mg/kg, respectively). These results show that endotoxin and its effects can be transferred from the liver graft donor to the recipient and that OLT per se reduces the recipient resistance to endotoxin with subsequent increase in mortality.

FK 506 renal toxicity and lack of detectable cytochrome P-450 3A in the liver graft of a patient undergoing liver transplantation

Many commonly used drugs are substrates for hepatic cytochrome P-450 3A in human beings, and its role in the metabolism of potentially toxic immunosuppressants has been highlighted (cyclosporine, FK 506). One hundred fifty human liver grafts were biopsied before and after liver transplantation, and levels of cytochromes P-450 3A, 1A2, 2D6 and 2C were estimated by means of the Western-blot technique and correlated with histological appearance, glycogen content and clinical course. In 15 of the grafts, cyclosporine oxidase was also measured, and in 12 of 15 recipients, urinary 6 beta-hydroxycortisol excretion was assayed. A wide range of cytochrome P-450 3A values were observed (25 to 366 arbitrary units/mg; mean, 105 +/- 63 arbitrary units/mg). In one graft (no. 730) no cytochrome P-450 3A was detectable on immunoblotting, despite increasing homogenate concentrations. In this sample, cytochromes P-450 1A2, 2D6, and 2C were present in normal ranges. Levels of cyclosporine oxidase and 6 beta-hydroxycortisol in the urine specimens of the recipient were found to be low. The recipient of graft 730 experienced reversible complications of FK 506 therapy despite adherence to the administration protocol and drug plasma level in the normal range. The subsequent appearance of the cytochrome P-450 3A was associated with the consequent tolerance of oral FK 506. The absence of detectable amounts of P-450 3A in one biopsy from a donated human liver graft dramatically emphasizes the extreme range of this enzyme levels and has important clinical implications.

[Relationship between hepatic cytochrome P-450 3A and acute cyclosporine toxicity in liver transplantation]

Despite the availability of whole blood cyclosporine assays, the different response of individual patients to its administration following transplantation continue to pose clinical problems, particularly in respect of toxicity. The aim of this study was to know if the inter-individual variations in the hepatic concentration of cytochrome P-450 3A, that metabolizes cyclosporine into several metabolites with very limited immunosuppressive activity, could be associated with cyclosporine toxicity. 59 consecutive liver transplant recipients were studied. Immunosuppression was with cyclosporine, azathioprine and methylprednisolone. The relative concentration of P-450 3A was assessed by immunoblot analysis using a specific monoclonal antibody on liver graft biopsy. Twelve patients experienced toxic neurological and renal complications. Six of these patients had cyclosporine levels in the therapeutic range. There was an excellent correlation between the occurrence of complications and cyclosporine whole blood levels (P < 10(-4), the first day post-op after a standard dose of cyclosporine (1 mg/kg). Cytochrome P-450 3A hepatic content assessed in a groups of 34 patients exhibited a 10-fold variation (m = 94 +/- 47 AU (Arbitrary Units)/mg). Eight of these patients who developed cyclosporine toxicity had a lower graft P-450 3A levels (m = 52 +/- 19 AU/mg, P = 3.10(-4), cf. patients with no toxicity). This highlights the importance of the first dose of cyclosporine and indicates that cytochrome P-450 3A can provide information which should allow individualized immunosuppression with cyclosporine maintaining therapeutic levels but avoiding toxicity in susceptible individuals.

Relationship between graft cytochrome P-450 3A content and early morbidity after liver transplantation

Cytochrome P-450 3A metabolizes CsA into several metabolites with very limited pharmacological activity and toxicity. In 40 liver donors, the relative concentrations of P-450 3A was assessed by immunoblot analysis using a specific monoclonal antibody exhibited a 10-fold variation (mean = 92 +/- 50 arbitrary units [AU]/mg) in levels. Problems consequent upon CsA usage (nephrotoxicity, neurotoxicity, and hypertension) occurred in 8 of 34 transplant recipients in the immediate postoperative period, and in these 8 patients the problems were always associated with low graft P-4503A levels (mean = 52 +/- 19 A.U./mg, P = 0.0003, cf. patients with no toxicity). Four of these patients had CsA levels that were also high, but 4 had CsA levels in the therapeutic range. Episodes of early graft rejection were related to higher P-450 3A levels (mean = 110 +/- 24 A.U./mg). Cytochrome P-450 3A levels were also found to be inversely related to CsA whole blood levels (assessed with a specific antibody 12 hr after the intravenous infusion of CsA at 1 mg/kg in the recipients (P < 0.02). Cytochrome P-450 3A can provide information that should allow individualized immunosuppression with CsA maintaining therapeutic levels but avoiding toxicity in susceptible individuals.

Incidence of adverse reactions to cyclosporine after liver transplantation is predicted by the first blood level

Despite the availability of whole-blood cyclosporine assays, the different responses of individual patients to its administration after transplantation continue to pose clinical problems, particularly with respect to toxicity. Fifty-seven recipients of first orthotopic liver transplants were studied between January 1992 and July 1992. Initial immunosuppression was carried out with azathioprine, methylprednisolone and cyclosporine, at a dose of 1 mg/kg/day adjusted to achieve blood levels between 400 and 600 ng/ml. Cyclosporine levels were measured 12 hr after the start of intravenous administration and correlated with the occurrence of toxic complications. Twelve patients experienced toxic complications in the first 7 days after orthotopic liver transplantation. These were neurological in six patients (of whom four also had kidney failure) and renal complications in the other six patients. All complications were reversed by reducing or stopping administration of cyclosporine. We noted excellent correlation between the occurrence of complications and cyclosporine whole-blood levels (p < 0.0001) despite the fact that levels did not exceed the therapeutic range. However, no correlation was observed between toxicity and cumulative dosage. In this study we were able to demonstrate that a standardized dose of cyclosporine does not prevent the occurrence of toxic side effects even when cyclosporine whole-blood levels are subsequently maintained in the therapeutic range. This highlights the importance of the first dose of cyclosporine and consequent early postoperative blood levels and indicates that these problems are unlikely to be overcome until a method of predicting individual requirements can be established in clinical practice.

Major pathway of imipramine metabolism is catalyzed by cytochromes P-450 1A2 and P-450 3A4 in human liver

The metabolism of imipramine by human liver microsomes was examined using a combination of five strategies. Human hepatic microsomes produced N-desmethylimipramine (84%), 2-hydroxyimipramine (10%), and 10-hydroxyimipramine (6%). Preincubation of human hepatocytes in culture with beta-naphthoflavone and macrolides exclusively induced the formation of desmethylimpramine (552%, p < 0.05, and 234%, p < 0.003, respectively). Correlations were obtained between rates of imipramine demethylation and cytochrome P-450 (P-450) 1A2 (r = 0.88, p < 0.001) and P-450 3A (r = 0.80, p < 0.02) concentrations in human liver microsomal preparations from 13 different subjects. Anti-P-450 1A2 and anti-P-450 3A antibodies selectively inhibited N-demethylation (80% and 60%, respectively). N-Demethylation was completely inhibited when anti-1A2 and anti-3A were added simultaneously. Kinetic studies with human microsomes confirm the contribution of two different enzymes in the N-demethylation. The Km of 1A2 was similar to the high affinity Km in human liver microsomes, whereas the Km of 3A was similar to the low affinity Km in human liver microsomes. P-450 1A2 was apparently more efficient than 3A4 (lower Km and higher Vmax) but was expressed in much lower concentration. Human P-450s 1A2 and 3A4 expressed in yeast efficiently produced desmethylimipramine. These results suggest that P-450 1A2 and P-450 3A4 are the major enzymes involved in imipramine N-demethylation in human hepatic microsomes. Similar experiments were conducted using P-450 2D6, and they confirmed that P-450 2D6 catalyzes imipramine 2-hydroxylation. Interindividual variations in 3A4 hepatic content may explain the large variations in imipramine blood levels observed after uniform dosages and thus may explain the variations in clinical efficacy. Caution might be advised in the clinical use of tricyclic antidepressants when drugs are also administered that induce or inhibit P-450s 3A4 and 1A2.

Characterization of mitochondrial imidazoline-guanidinium receptive sites (IGRS) in liver

Some imidazoline and guanidinium antihypertensive drugs display high affinity for a nonadrenergic membrane protein, the imidazoline-guanidinium receptive site (IGRS), which is insensitive to catecholamine and physically distinct from alpha 2-adrenoceptor. In the present report, we characterized IGRS in human and rabbit liver using [3H]idazoxan as radioligand. By performing subcellular fractionation, we showed a significant increase in [3H]idazoxan binding sites on membrane fractions enriched in cytochrome oxidase activity, a mitochondrial marker. A further enrichment in [3H]idazoxan binding (53-fold with respect to the homogenate) was found in a purified preparation of mitochondrial outer membranes. This localization of IGRS will facilitate the characterization of its functional activity in liver.

[Conflict between psoas and total hip prosthesis]

This conflict leads to a chronic irritation of the psoas by the antero-medial part of the cup, but it has been poorly described in the past. A study of six patients suffering from this trauma, and who were re-operated revealed that the muscle was worn thin in front of the prominent cup. In the case of 4 of the 6 patients pain had started to occur shortly after total hip replacement. The following symptoms were noted among all 6 patients: pain was suffered during flexion--extension movements--walking up stairs--arising from a chair. Pressure on the medial part of the groin was painful, especially during active elevation of the lower limb. Passive mobility was normal and painless. Psoas bursitis was observed in three cases. The main cause of this conflict is the protrusion of the cup beyond the antero-medial edge of the acetabulum; this protrusion may be either due to a bone graft or a bit of cement, but most often an acetabular insufficiency (congenital dysplasia) favors the formation of this anterior overhang. The spiral cup screwed into the bone can be especially aggressive when it protrudes. Treatment includes the resection of the overhang, but post-operative results will be uncertain unless the resection is really complete. In the case of 4 patients the results of such an intervention were only mild to poor. This problem can be avoided by proper care and preventive measures in the original replacement avoiding all projections beyond the anterior edge of the acetabulum--cup, bone graft, cement, especially if dysplasic.(ABSTRACT TRUNCATED AT 250 WORDS)

Hormonal regulation of microsomal flavin-containing monooxygenase: tissue-dependent expression and substrate specificity

The substrate- and tissue-dependent hormonal regulation of flavin-containing monooxygenase (EC 1.14.13.8) was studied in male and female rats. Hypophysectomy of males reduced liver microsomal N,N-dimethylaniline N-oxidation, thiobenzamide S-oxidation, and imipramine N-oxidation, although the reduction was not as marked with the latter substrate. Castration also reduced flavin-containing monooxygenase-dependent activities, but not to the same extent as hypophysectomy. Administration of growth hormone or testosterone to hypophysectomized males only partially restored basal activities. In female rats, hypophysectomy had no effect on N,N-dimethylaniline N-oxidation or thiobenzamide S-oxidation and actually stimulated imipramine N-oxidation (98%). These effects were demonstrated to be tissue- and sex-dependent. For example, hypophysectomy markedly (300%) enhanced imipramine N-oxidation in male kidney and significantly decreased the same activity in male and female lung. Correlations between levels of the enzyme determined by immunoquantitation (with antibody to the rat liver enzyme) and activities toward these three substrates, in male and female liver, lung, and kidney, also provide evidence for the existence of multiple forms of flavin-containing monooxygenase, which appear to be under different hormonal regulation.

Metabolism of the chloroethylnitrosoureas

1. The chemical degradation and metabolism of the 2-chloroethylnitrosoureas (CENUSs) have been critically reviewed with the objective of gaining a better understanding of factors that could aid in the design of new, more effective, anticancer drugs. 2. The CENUs are chemically unstable under normal physiological conditions and can rapidly degrade to give a variety of reactive intermediates capable of carbamoylating proteins and/or alkylating both proteins and DNA. 3. Carbamoylation is thought to make a minimal contribution to the cytotoxic effect of the CENUs, although it may be involved in some of the unwanted side-effects. It would seem desirable, therefore, to design new CENUs with low carbamoylating activity. 4. The main action of the CENUs is by alkylation of DNA via a chloroethyldiazo-hydroxide intermediate. Chloroethylation is important, as opposed to hydroxyethylation, since the former leads to inter-strand DNA cross-linking via an intramolecular rearrangement with the removal of chloride. It is this inter-strand cross-linking which prevents subsequent DNA repair and loss of cytotoxicity. 5. Metabolism usually, although not exclusively, leads to deactivation of the CENUs either by dechlorination or denitrosation of the molecule, generally with the former being the dominant route. These reactions occur very rapidly, and before chemical degradation can take place, and can be an important determinant in the final cytotoxicity. Moreover, both these pathways involve the cytochrome P-450 system and can be induced with phenobarbital.(ABSTRACT TRUNCATED AT 250 WORDS)