Growth of Hodgkin cell lines in severely combined immunodeficient mice.

No animal model exists for the in vivo growth of Hodgkin's-lymphoma-derived cells. Neither unmanipulated Hodgkin's-disease(HD)-derived cell lines nor primary biopsy tissue could be grown in nude mice. Since the severe combined immunodeficient (SCID) mouse has been reported to be a better recipient for transplanted human lymphatic tissue than the nude mouse, we tested whether SCID mice provide suitable conditions for the in vivo growth of HD cell lines. Tumorigenicity of HD cells was tested in untreated and pre-treated SCID mice and in another combined immunodeficient mouse strain, beige/nude/X-linked immunodeficient (BNX) mouse. SCID mice supported in vivo growth of the 6 HD cell lines tested (L428, L540, L591, DEV, HD-LM2, KM-H2). Only one of the 6 lines (DEV) was tumorigenic in BNX mice. No HD cell line proliferated in T-cell-deficient nude mice. Thus, in vivo growth of HD cell lines appeared to be related to the degree of host immunodeficiency. Additional growth supportive treatments such as fibrosarcoma co-transplantation, intraperitoneal mineral oil injection or immunosuppressive pre-treatment (anti-asialo-GMI-antibody injection) permitted growth of 3 additional HD cell lines in BNX mice. The immunophenotype and karyotype of explanted graft cells were identical to the original cell lines. Our experiments describe an effective and reproducible xenograft model for growth of Hodgkin's-disease-derived cell lines. This may be of value for elucidating the growth characteristics of Hodgkin's-lymphoma-derived cells as well as for testing new therapeutic regimens.     

Stability and variability in hormonal responses to prolonged exercise.

To study the dynamics of alterations in blood hormones and their individual variability during prolonged exercise, changes in plasma levels of corticotropin, cortisol, aldosterone, testosterone, progesterone, somatotropin, insulin and C-peptide were recorded in 32 endurance athletes and 50 untrained persons during a 2-hour exercise on a cycle ergometer at 60% VO2max. Common changes were activation of the pituitary corticotropin function, mostly at the end of exercise, rises in aldosterone and somatotropin concentrations and decreases in insulin and C-peptide levels during exercise. The activation of pituitary-adrenocortical system and the decrease of insulin but not C-peptide levels were more pronounced in athletes than in untrained persons. A large inter-individual variability existed in changes of cortisol, testosterone and progesterone in both groups. Five variants were found in the dynamics of cortisol concentration. Whereas the alterations of corticotropin were characterized mainly by a biphasic increase, the dynamics of corticotropin and cortisol coincided only in one variant out of five. Most characteristic for the postexercise recovery period were decreased activity of the pituitary-adrenocortical system and delayed normalization of aldosterone level.     

A mouse model for alpha-methylacyl-CoA racemase deficiency: adjustment of bile acid synthesis and intolerance to dietary methyl-branched lipids

alpha-Methylacyl-CoA racemase (Amacr) deficiency in humans leads to sensory motor neuronal and liver abnormalities. The disorder is recessively inherited and caused by mutations in the AMACR gene, which encodes Amacr, an enzyme presumed to be essential for bile acid synthesis and to participate in the degradation of methyl-branched fatty acids. To generate a model to study the pathophysiology in Amacr deficiency we inactivated the mouse Amacr gene. As per human Amacr deficiency, the Amacr(-/-) mice showed accumulation (44-fold) of C27 bile acid precursors and decreased (over 50%) primary (C24) bile acids in bile, serum and liver, however the Amacr(-/-) mice were clinically symptomless. Real-time quantitative PCR analysis showed that, among other responses, the level of mRNA for peroxisomal multifunctional enzyme type 1 (pMFE-1) was increased 3-fold in Amacr(-/-) mice. This enzyme can be placed, together with CYP3A11 and CYP46A1, to make an Amacr-independent pathway for the generation of C24 bile acids. Exposure of Amacr(-/-) mice to a diet supplemented with phytol, a source for branched-chain fatty acids, triggered the development of a disease state with liver manifestations, redefining the physiological significance of Amacr. Amacr is indispensable for the detoxification of dietary methyl-branched lipids and, although it contributes normally to bile acid synthesis from cholesterol, the putative pMFE-1-mediated cholesterol degradation can provide for generation of bile acids, allowing survival without Amacr. Based upon our mouse model, we propose elimination of phytol from the diet of patients suffering from Amacr deficiency.     

Combined haplotype analysis of the interleukin-19 and -20 genes: relationship to plaque-type psoriasis

There is increasing evidence to suggest that the newly discovered cytokines interleukin (IL)-19 and -20 have a role in the function of epidermis and in psoriasis. The genes encoding these cytokines locate into the genomic IL-10 region on human chromosome 1. The aim of the present study was to analyze whether single-nucleotide polymorphisms (SNPs) in these genes have an impact on the susceptibility for psoriasis. From pairwise linkage disequilibrium (LD) matrix of the IL-19 and -20 gene polymorphisms, what reflects the nonrandom association of alleles at these markers, it was apparent that IL-19 and -20 genes form one block of LD. We found that the HT3 CACCGGAA haplotype of the IL-19 and -20 genes was associated with an increased risk of psoriasis, reflecting its role in determining susceptibility to plaque-type psoriasis. Although association analysis of the IL-19 gene indicated that minor alleles of the IL-19 gene SNPs (rs2243188, rs2243169 and rs2243158) revealed protective effect to psoriasis and haplotype analysis of the IL-19 gene proved significant protective effect of the TGATA haplotype in case of late-onset disease, combined haplotype analysis of the IL-19 and -20 genes demonstrated that protective effect of the IL-19 gene is secondary to the susceptibility effect of the IL-20 gene.     

Cholesterol metabolism and non-cholesterol sterols in patients with ileal pouch anastomosis

Background: Previous studies suggest only minor changes in bile acid metabolism after panproctocolectomy with ileal pouch construction.Aims/Methods: To investigate these changes further, we studied cholesterol absorption and serum, biliary and fecal non-cholesterol sterols and lipids in 12 ileal pouch patients and 10 controls.Results: In patients, cholesterol absorption was markedly reduced and was associated with low serum total and LDL cholesterol and LDL triglyceride levels, but surprisingly, cholesterol synthesis, as indicated by sterol-balance data or serum cholesterol precursor levels, was within low normal limits. The high proportions of serum plant sterol to cholesterol, particularly that of campesterol, were not related to cholesterol absorption, but were attributable to a markedly reduced biliary cholesterol secretion. Interestingly, in these patients the fractional absorption of campesterol was normal, whereas that of sitosterol, like cholesterol, was reduced and was positively related to the intestinal influx of cholesterol. The patients' serum cholestanol proportion was normal, but the proportion of the cholestanol formed during intestinal passage was significantly reduced (17.9% vs 65.2% in controls).Conclusions: Thus ileal pouch patients are characterized by sterol malabsorption, lowered serum total and LDL-cholesterol levels, but unexpectedly without any increase in cholesterol synthesis. The lack of high serum cholestanol, shown earlier frequently in unoperated patients with ulcerative colitis, may indicate reversible cholestasis, a finding deserving further exploration.     

Ex vivo treatment of proliferating human cord blood stem cells with stroma-derived factor-1 enhances their ability to engraft NOD/SCID mice

Ex vivo proliferation of hematopoietic stem cells (HSCs) is important for cellular and gene therapy but is limited by the observation that HSCs do not engraft as they transit S/G(2)/M. Recently identified candidate inhibitors of human HSC cycling are transforming growth factor-beta(1) (TGF-beta(1)) and stroma-derived factor-1 (SDF-1). To determine the ability of these factors to alter the transplantability of human HSCs proliferating in vitro, lin(-) cord blood cells were first cultured for 96 hours in serum-free medium containing Flt3 ligand, Steel factor, interleukin-3, interleukin-6, and granulocyte colony-stimulating factor. These cells were then transferred to medium containing Steel factor and thrombopoietin with or without SDF-1 and/or TGF-beta(1) for 48 hours. Exposure to SDF-1 but not TGF-beta(1) significantly increased (> 2-fold) the recovery of HSCs able to repopulate nonobese diabetic/severe combined immunodeficiency mice. These results suggest new strategies for improving the engraftment activity of HSCs stimulated to proliferate ex vivo.     

Increased gene transfer into human hematopoietic progenitor cells by extended in vitro exposure to a pseudotyped retroviral vector

Retroviral-mediated gene transfer is the most attractive modality for gene transfer into hematopoietic stem cells. However, transduction efficiency has been low using amphotropic Moloney murine leukemia virus (MoMLV) vectors. In this study, we investigated modifications of gene transfer using amphotropic MoMLV vectors in cell-free supernatant for their ability to increase the currently low transduction of both committed hematopoietic progenitors, granulocyte-macrophage colony- forming units (CFU-GMs), and their precursors, long-term culture- initiating cells (LTC-IC). First, based on the observation that bone marrow cells express more gibbon ape leukemia virus (GALV) receptor (Glvr-1) than amphotropic receptor (Ram-1), PG13/LN, which is a MoMLV vector pseudotyped with the GALV envelope, was compared with the analogous amphotropic envelope vector (PA317/LN). Second, progenitor cell transduction efficiency was compared between CD34 enriched and nonenriched progenitor populations. Third, the duration of transduction in vitro was extended to increase the proportion of progenitor cells that entered cell cycle and could thereby integrate vector cDNA. In 20 experiments, 1 x 10(6) marrow or peripheral blood mononuclear cells (PBMCs)/mL were exposed to identical titers of pseudotyped PG13/LN vector or PA317/LN vector in the presence of recombinant human interleukin-1 (IL-1), IL-3, IL-6, and stem cell factor (SCF; c-kit ligand) for 5 days. 50% of fresh vector supernatant was refed daily. Hematopoietic progenitor cells as measured by G418-resistant granulomonocytic colony (CFU-GM) formation were transduced more effectively with PG13/LN (19.35%) than with PA317/LN (11.5%, P = .012). In 11 further experiments, enrichment of CD34 antigen positive cells significantly improved gene transfer from 13.9% G418-resistant CFU-GM in nonenriched to 24.9% in CD34-enriched progenitor cells (P < .01). To analyze gene transfer after extended growth factor-supported long-term culture, 1 x 10(6) marrow cells/mL were cultured with IL-1, IL-3, IL-6, and SCF (50 ng/mL each) for 1, 2, and 3 weeks. Fifty percent of PG13/LN supernatant with growth factors was refed on 5 days per week. Five percent of marrow CFU-GM and 67% of LTC-IC were G418 resistant at 1 week (n = 4), 60% of CFU-GM and 100% of LTC-IC were resistant at 2 weeks (n = 2) and 74% of CFU-GM (n = 4) and 82% of LTC-IC (n = 2) were resistant at three weeks.(ABSTRACT TRUNCATED AT 400 WORDS)