Adult porcine islet transplantation in baboons treated with conventional immunosuppression or a non-myeloablative regimen and CD154 blockade

The aim of the present study was to assess the survival of adult porcine islets transplanted into baboons receiving either (I) conventional triple drug immunosuppressive therapy or (2) a non-myeloablative regimen and an anti-CD154 monoclonal antibody (mAb) aimed at tolerance-induction. Group 1 baboons (n = 3) were pancreatectomized prior to intraportal injection of 10,000 porcine islet equivalents (IE)/kg and immunosuppressed with anti-thymocyte globulin (ATG), cyclosporine and azathioprine. In Group 2 (n = 2), non-pancreatectomized baboons underwent induction therapy with whole body and thymic irradiation, and ATG. Extracorporeal immunoadsorption (EIA) of anti-Galalpha1,3Gal (Gal) antibody was carried out. Maintenance therapy was with cobra venom factor, cyclosporine. mycophenolate mofetil, methylprednisolone and anti-CD154 mAb. Porcine islets were injected intraportally (14,000 and 32,000 IE/kg, respectively) and high-dose pig mobilized peripheral blood progenitor cells (3 x 10(10) cells/kg) were infused into a systemic vein. Porcine islets were also implanted in the sternomastoid muscle to facilitate subsequent biopsies. In both groups. porcine C-peptide was measured, and histological examination of liver or sternomastoid muscle biopsies was performed at regular intervals. In Group 1, total pancreatectomy reduccd human C-peptide to < 0.1 ng/ml and induced insulin-requiring diabetes. The transplantation of porcine islets was followed by normalization of glycemia for 15-24 h. Porcine C-peptide was detected only transiently immediately after porcine islet injection (maximum 0.12 ng/ml). Histological examination of liver biopsies taken between days 2 and 19 did not reveal viable islets, but necrotic cell structures with mononuclear cell infiltrates were identified in portal venules. In Group 2, injection of porcine islets into non-pancreatectomized recipients induced a transient hypoglycemia (2-4 h) requiring concentrated intravenous dextrose administration. Porcine C-peptide was detectable for 5 and 3 days (maximum 2.8 and 1.0 ng/ml), respectively. Baboon #4 died on day 12 from small bowel intussusception. Liver and sternomastoid muscle biopsies showed well-preserved porcine islets, staining positive for insulin and glucacon, without signs of rejection. In baboon #5, viable islets were detected in the sternomastoid muscle biopsy on day 14, but not on day 28 or thereafter. A progressive mononuclear cell and macrophage infiltration was seen in the biopsies. In conclusion, conventional immunosuppression allowed survival of porcine islets in baboons for < 24 h. The non-myeloablative regimen prolonged survival of porcine islets for > 14 days. However, despite depletion of T cells, anti-Gal antibody and complement, and CD154-hlockade, porcine islets were rejected by day 28. These results suggest that powerful innate immune responses are involved in rejection of discordant xenogencic islets.     

Anti-Gal alpha 1-3Gal IgM and IgG antibody levels in sera of humans and old world non-human primates

Organs transplanted from pig to primate are rejected within minutes or hours by an antibody-dependent, complement-mediated mechanism [hyperacute rejection (HAR)]. Even after depletion of anti-Galα1-3Gal (Gal) antibody (Ab), for example by extracorporeal immunoadsorption, return of natural Ab is believed to be a major factor in the initiation of acute humoral xenograft rejection. Various non-human primates are used as recipients of pig organs in experimental discordant xenotransplantation (XTx) models. However, anti-Gal IgM and IgG levels in non-human primates may differ from those in humans. Serum levels of anti-Gal IgM and IgG were measured by enzyme-linked immunosorbent assay (ELISA) in humans (n=14), chimpanzees (n=8), baboons (n=214), cynomolgus monkeys (n=29), rhesus monkeys (n=23) and Japanese monkeys (n=6). The mean level of anti-Gal IgM was significantly higher in chimpanzees than in other groups, while in rhesus monkeys it was significantly lower than in other groups, except baboons and Japanese monkeys. The mean human anti-Gal IgG level was higher than in other groups and this difference reached statistical significance except with regard to chimpanzees. The mean anti-Gal IgG level in baboons was significantly lower than that in humans, chimpanzees and cynomolgus monkeys. The measured differences in anti-Gal IgM and IgG levels may affect the kinetics of Ab removal and rate of return in different species, and thus may have relevance for translating work in non-human primate models to the clinical setting.     

Effects of lerisetron,a new 5-HT3 receptor antagonist,on ipecacuanha-induced emesis in healthy volunteers

The purpose of these studies was to evaluate the effect of lerisetron (1-phenyl-methyl-2-piperazinyl-1H-benzimidazole hydrochloride, CAS 143257-98-1, F-0930-RS2), a new 5-HT3 receptor antagonist, on ipecacuanha-induced nausea and vomiting. The ipecacuanha model of emesis has been used to test the anti-emetic activity of several different 5-HT3 antagonists and the anti-emetic doses that were effective in the ipecacuanha model have been found to correlate well with the clinically effective doses. Study 1 investigated oral doses of lerisetron from 4 mg to 40 mg. Study 2 evaluated the duration of effect of a single dose of 20 mg oral lerisetron. Study 3 evaluated intravenous doses of 18 mg and 12 mg lerisetron. In Study 1, the 40 mg dose of oral lerisetron inhibited emesis in all test subjects. The percentage of subjects who experienced an emetic episode increased as the dose of lerisetron decreased. At the lowest dose level tested five of six subjects had an emetic episode compared with four out of five in the placebo group. In Study 2, 20 mg oral lerisetron was effective up to 12 h after administration. When ipecacuanha was administered at 18 h post-dose three of seven subjects had an emetic episode and at 24 h post-dose the incidence of emesis was similar to the placebo treatment groups in the previous study. Study 3 demonstrated the effectiveness of intravenous doses of lerisetron. The 18 mg intravenous dose reduced the number of patients experiencing emetic episodes by 75% compared with placebo, doses below 12 mg i.v. were not evaluated because of the reduced efficacy of the compound at this dose level. In conclusion, lerisetron has been shown to be effective in the treatment of ipecacuanha-induced nausea and vomiting at intravenous doses of 18 mg and at oral doses of 20 mg for up to 12 hours.     

The effect of fluconazole on the pharmacokinetics of rosuvastatin

OBJECTIVE: To examine the effect of fluconazole, a potent inhibitor of CYP2C9 and CYP2C19, on the pharmacokinetics of rosuvastatin in healthy volunteers. Significantly increased plasma concentrations of fluvastatin have been observed following co-administration with fluconazole. METHODS: This was a randomised, double-blind, two-way crossover, placebo-controlled trial. Healthy male volunteers ( n=14) were given fluconazole 200 mg or matching placebo once daily for 11 days; rosuvastatin 80 mg was co-administered on day 8 of dosing. Plasma concentrations of rosuvastatin, N-desmethyl rosuvastatin, and active and total 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors were measured up to 96 h post-dose. RESULTS: Following co-administration with fluconazole, rosuvastatin geometric least-square mean area under the plasma concentration-time curve (AUC(0-t)) and peak plasma concentration (C(max)) were increased by 14% and 9%, respectively, compared with placebo (90% confidence intervals for the treatment ratios: 0.967 to 1.341 and 0.874 to 1.355, respectively). Individual treatment ratios for AUC(0-t) ranged from 0.59 to 2.23, and for C(max) ranged from 0.52 to 2.28. The limited data available for the N-desmethyl metabolite show that geometric mean C(max) was decreased by approximately 25% compared with placebo. Rosuvastatin accounted for essentially all of the circulating active HMG-CoA reductase inhibitors and most (>90%) of the total inhibitors. Fluconazole did not affect the proportion of circulating active or total inhibitors accounted for by circulating rosuvastatin. CONCLUSIONS: Fluconazole produced only small increases in rosuvastatin AUC(0-t) and C(max), which were not considered to be of clinical relevance. The results support previous in-vitro findings that CYP2C9 and CYP2C19 metabolism is not an important clearance mechanism for rosuvastatin.     

Health-related quality of life in patients 7 months after a myocardial infarction: factors affecting the Short Form-12

We assessed patients' health-related quality of life after myocardial infarction and identified related variables. Clinical data were obtained retrospectively from medical records of consecutive patients admitted to a Midwestern university-affiliated medical center with diagnosis of myocardial infarction from July 1999-July 2000. Telephone interviews 7 months after discharge were made to administer the Short Form-12 (SF-12) and obtain patient, disease, drug, and intervention data. Complete information was obtained from 200 patients (mean age 63.4 +/- 13.1 yrs, 68% men). The mean Physical Component Summary (PCS)-12 score was 40.6 +/- 12.0, and the mean Mental Component Summary (MCS)-12 score was 52.1 +/- 10.0. Based on univariate analyses, low PCS-12 scores were associated with women; non-Q-wave infarctions; greater number of illnesses; history of myocardial infarction, chronic heart failure (CHF), transient ischemic attack (TIA), renal disease, peripheral vascular disease, or percutaneous coronary intervention (PCI); rehospitalization during the interim period; and unscheduled PCI since index myocardial infarction. Low MCS-12 scores were associated with age below 65 years, low overall self-reported drug therapy compliance, low self-reported compliance with angiotensin-converting enzyme inhibitor and lipid-lowering therapy, no history of coronary artery bypass graft, and no stress test since index myocardial infarction. A multivariate regression model for PCS-12 kept the following variables: greater number of illnesses, history of CHF or TIA, and rehospitalization since index myocardial infarction. The MCS-12 model contained age below 65 years, low overall compliance, and low compliance with lipid-lowering therapy. Further work is necessary to determine noncardiovascular predictors of quality of life and whether interventions for these patients will result in improved quality of life.     

Single or group housing altered hormonal physiology and affected pituitary and interstitial cell kinetics

A significant negative correlation between testicular interstitial cell tumors and pituitary tumors in control male F344 rats has been reported associated with the number of animals per cage. Change in numbers of animals per cage may cause stress and increased serum corticosteroids that can impair testosterone synthesis by interstitial cells. Eventual atrophy of interstitial cells may result in pituitary hyperfunction and tumor development. For relevant risk assessments, understanding the effect husbandry has on cellular processes is necessary. Twenty-four 6-week-old male F344 rats were housed individually, as pairs, or as trios for 13 weeks. Measured parameters included feed consumption, body and organ weights, hemograms, hormonal levels, histopathology, and cellular kinetics in the pituitary and testicle. Several caging-related differences occurred, that, although not statistically different, could be biologically significant; these included increased serum levels of estradiol, progesterone, and corticosterone; increased spermatogonial proliferation; decreased apoptosis within seminiferous tubules; and increased BrdU immunoreactivity of the interstitial cells. The statistically significant decrease in lymphocyte numbers correlated with the associated increase in corticosterone levels. This study indicates that the number of animals in a cage is associated with hormonal and cellular kinetic changes in the pituitary and testes, which could influence the incidence of tumors in these organs.     

DNA vaccine expressing conserved influenza virus proteins protective against H5N1 challenge infection in mice

Influenza vaccination practice, which is based on neutralizing antibodies, requires being able to predict which viral strains will be circulating. If an unexpected strain, as in the 1997 H5N1 Hong Kong outbreak, or even a pandemic emerges, appropriate vaccines may take too long to prepare. Therefore, strategies based on conserved influenza antigens should be explored. We studied DNA vaccination in mice with plasmids expressing conserved nucleoprotein (NP) and matrix (M) from an H1N1 virus. After vaccination, mice were challenged with A/H5N1 viruses of low, intermediate, and high lethality. A/NP+A/M DNA vaccination reduced replication of A/Hong Kong/486/97 (HK/486), a nonlethal H5N1 strain, and protected against lethal challenge with more virulent A/Hong Kong/156/97 (HK/156). After HK/156 exposure, mice survived rechallenge with A/Hong Kong/483/97 (HK/483), although the DNA vaccination alone protected poorly against this highly virulent strain. In the absence of antigenically matched hemagglutinin-based vaccines, DNA vaccination with conserved influenza genes may provide a useful first line of defense against a rapidly spreading pandemic virus.