Polyamine alterations in blood of male homozygotes and heterozygotes for cystic fibrosis

Clinical Phenotypes of Cystic Fibrosis Carriers

Cystic fibrosis (CF) is an autosomal recessive genetic disorder caused by mutations in CFTR, the cystic fibrosis transmembrane conductance regulator gene. People with CF experience a wide variety of medical conditions that affect the pulmonary, endocrine, gastrointestinal, pancreatic, biliary, and reproductive systems. Traditionally, CF carriers, with one defective copy of CFTR, were not thought to be at risk for CF-associated diseases. However, an emerging body of literature suggests that heterozygotes are at increased risk for many of the same conditions as homozygotes. For example, heterozygotes appear to be at increased risk for chronic pancreatitis, atypical mycobacterial infections, and bronchiectasis. In the United States alone, there are almost 10 million CF carriers. Universal newborn screening and prenatal genetic screening will identify more. Thus, there is a critical need to develop more precise estimates of health risks attributable to the CF carrier state across the lifespan.

Acute pancreatitis induced by activated polyamine catabolism is associated with coagulopathy: effects of alpha-methylated polyamine analogs on hemostasis

BACKGROUND/AIMS

Polyamines are ubiquitous organic cations essential for cellular proliferation and tissue integrity. We have previously shown that pancreatic polyamine depletion in rats overexpressing the catabolic enzyme, spermidine/spermine N(1)-acetyltransferase (SSAT), results in the development of severe acute pancreatitis, and that therapeutic administration of metabolically stable alpha-methylated polyamine analogs protects the animals from pancreatitis-associated mortality. Our aim was to elucidate the therapeutic mechanism(s) of alpha-methylspermidine (MeSpd).

METHODS

The effect of MeSpd on hemostasis and the extent of organ failure were studied in SSAT transgenic rats with either induced pancreatitis or lipopolysaccharide (LPS)-induced coagulopathy. The effect of polyamines on fibrinolysis and coagulation was also studied in vitro.

RESULTS

Pancreatitis caused a rapid development of intravascular coagulopathy, as assessed by prolonged coagulation times, decreased plasma fibrinogen level and antithrombin activity, enhanced fibrinolysis, reduced platelet count and presence of schistocytes. Therapeutic administration of MeSpd restored these parameters to almost control levels within 24 h. In vitro, polyamines dose-dependently inhibited fibrinolysis and intrinsic coagulation pathway. In LPS-induced coagulopathy, SSAT transgenic rats were more sensitive to the drug than their syngeneic littermates, and MeSpd-ameliorated LPS-induced coagulation disorders.

CONCLUSION

Pancreatitis-associated mortality in SSAT rats is due to coagulopathy that is alleviated by treatment with MeSpd.

Analysis of polyamines as markers of (patho)physiological conditions

The aliphatic polyamines, putrescine, spermidine and spermine, are normal cell constituents that play important roles in cell proliferation and differentiation. The equilibrium between cellular uptake and release and the balanced activities of biosynthetic and catabolic enzymes of polyamines are essential for normal homeostasis in the proliferation and functions of cells and tissues. However, the intracellular polyamine content increases in hyperplastic or neoplastic growth. Although the involvement of polyamines in physiological and pathological cell proliferation and differentiation has been well established, the role they play is quite different in relation to cell systems and animal models and is dependent on inducer agents and stimuli. Also, the experimental procedures used to deplete polyamines have been shown to influence the cell responses. In this paper, the assay methods currently in use for polyamines are reviewed and compared with respect to sensitivity, reproducibility and applicability to routine analysis. The relevance of polyamine metabolism and the uptake/release process in many physiological and pathological processes is highlighted, and the cellular polyamine pathways are discussed in relation to the possible diagnostic and therapeutic significance of these mediators.

Successful treatment of lupus nephritis in MRL-lpr/lpr mice by inhibiting ornithine decarboxylase

Ornithine decarboxylase (ODC) is a key enzyme in the biosynthesis of cellular polyamines, putrescine, spermidine and spermine. Difluoromethylornithine (DFMO) is an irreversible inhibitor of ODC and thereby depletes putrescine and spermidine levels in vivo and in vitro. Previous studies in lupus-prone MRL-lpr/lpr mice treated with 1% DFMO in drinking water have been associated with improved lifespan, and reduced anti-DNA antibody production, lymphadenopathy, and splenic polyamine levels. Since glomerulonephritis is a major cause of morbidity and mortality in lupus, we studied the effect of DFMO on renal histology of MRL-lpr/lpr mice. Female BALB/c and MRL-(+)/+ mice were used as controls. Dose response studies revealed that 1.5% DFMO in drinking water had maximum therapeutic efficacy and produced a significant 79% increase in the median lifespan of a group of 20 mice compared to an equal number of controls (P less than 0.001). Renal histologic studies were performed on kidney sections from four to five mice each from DFMO-treated and untreated groups at 12, 16, 20, 24 and 29 weeks of age. Sections were read blinded to duration and treatment and scored by four major histologic criteria (glomerulonephritis, interstitial inflammation, perivascular inflammation, and vasculitis) and showed significant reduction in all these parameters in DFMO-treated mice when compared to age- and sex-matched untreated mice of the same strain. DFMO treatment had no significant effect on pulmonary histologic findings on these mice. DFMO treatment reduced ODC activity and polyamine concentrations in treated mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Transglutaminase in erythrocytes of cystic fibrosis patients

Transglutaminase activity was determined in erythrocytes from patients with cystic fibrosis and control subjects. No differences were observed between the two groups either for enzymatic activity or for the activating effect of calcium ions. The previously described abnormal metabolism of polyamines in cystic fibrosis cannot be related to an altered function of transglutaminases.

Galactosyltransferases: physical, chemical, and biological aspects

Galactosyltransferases (GTs) are one of the members of a family of enzymes called glycosyltransferases involved in the biosynthesis of complex carbohydrates. These enzymes catalyze the transfer of galactose from UDP-galactose to an acceptor (glycoprotein, glycolipid) containing terminal N-acetylglucosamine or N-acetylgalactosamine residue. GTs occur in soluble (milk, serum, effusions, etc.) and insoluble (membrane) forms. The GT activities on the outer surface of the cells have been correlated with a host of cellular interactions, including fertilization, cell migration, embryonic induction, chondrogenesis, contact inhibition of growth, cell adhesion, hemostasis, intestinal cell differentiation, and immune recognition. GTs have been purified to homogeneity using affinity chromatography. Most GTs are found active in the pH range 6 to 8 and at temperatures between 35 to 40 degrees C. Manganese is an essential co-factor for GT activity. Isoenzymes of GT have been recognized, especially in tumor tissues, malignant effusions, and sera of cancer patients using polyacrylamide gel electrophoresis in the presence and absence of SDS. Depending on the source of the enzyme, the molecular weights of GTs range between 40,000 to 80,000 daltons. Carcinoma-associated GT isoenzyme has been reported to have a higher molecular weight than the normal GT isoenzyme. Development of monoclonal antibody against the cancer-specific GT isoenzyme will provide help in the development of an immunoassay for the measurement of this isoenzyme in the sera and an aid in the radioimmunolocalization of the tumors in cancer patients.

Changes in diamine and polyamine metabolism in the duct-ligated submaxillary and sublingual glands of the rat

Duct-ligation of salivary glands is known to cause disappearance of acini, while ductal elements persist. In the present investigation the duct-ligated submaxillary and sublingual glands increased in weight by 45-60% 3 days postoperatively, while they weighed 48-56 and 63-64% less than their contralateral glands 10 and 21 days postoperatively. In the duct-ligated glands putrescine increased markedly both in terms of total amount and in terms of concentration, while spermidine and spermine decreased; histamine, in terms of concentration, was initially reduced but increased markedly later. As to total amount histamine tended to increase along time. The histamine-forming enzyme, histidine decarboxylase, and the putrescine-forming enzyme, ornithine decarboxylase, showed higher activities in the duct-ligated submaxillary glands than in the contralateral glands. Di- and polyamines and their synthesizing enzymes are considered to increase in growing tissue. The present results of increased amine levels and enzyme activities are discussed in relation to previous findings of ductal goblet cell hyperplasia following duct-ligation and of increases of polyamines in cystic fibrosis.

Clinical relevance of polyamines

The polyamines, putrescine, spermidine, and spermine have been established as biochemical markers of normal and pathological growth. In malignancy, the urinary concentrations of spermidine reflect the tumor cell loss and the urinary level of putrescine is related both to the number of tumor cells in cell cycle and to the tumor cell loss factor. A greater than twofold increase in urinary spermidine within 72 hr of chemotherapy predicts a complete or a partial response with a high degree of accuracy. Urinary putrescine may be valuable, not only in assessing the early response to therapy but also in determining whether the chemotherapy promotes a later burst of cell proliferation. Erythrocyte spermidine concentrations also appear to track alterations in tumor kinetics. Alterations in intracellular and extracellular polyamines in other pathologies such as psoriasis, muscular dystrophy, and cystic fibrosis also accurately reflect the disease activity and, in those cases studied, response to therapy. Therefore, the determination of polyamine concentrations in extracellular fluids and in erythrocytes allows for (1) the early assessment of response to multimodality therapy, (2) disease or tumor staging, and (3) assessment of disease activity including long-term monitoring of polyamine concentrations to pinpoint remission and relapse in adjuvant patients. Information obtained by the monitoring of polyamines could result in prolongation of survival time of patients as well as assist in the design of the most effective therapy regimen for the pathology. Since other such specific kinetic markers are not available, polyamines should be clinically utilized to track tumor evolution and tumor response to therapy in those patients at high risk, in which such measurements could be translated into therapeutic efficacy.

Evidence for natural antibodies (IgG) to polyamines in human sera

Human sera contain IgGs that react with latex-putrescine spheres. Identification of the IgGs has been achieved by polyacrylamide gel electrophoresis and their reaction with peroxidase-labeled antihuman gamma-chain-specific antibodies. The inhibition of IgG fixation to latex-putrescine spheres by free spermine and putrescine provides evidence that these IgGs are specific for polyamines.

Cystic fibrosis: decreased conjugation and excretion of [14C]spermidine

Free and conjugated [14C]spermidine were measured in plasma samples from normal individuals and cystic fibrosis patients. Within 4 minutes, the 14C-labeled material in the plasma from normal individuals was 70 percent conjugated compared to no detectable conjugation by cystic fibrosis patients. Further, the patients excreted only 11 to 13 percent of the [14C]spermidine in their urine within 72 hours whereas normal excretion was 60 to 76 percent. In both cases, the labeled material was in a conjugated form.

Membrane function in cystic fibrosis. II. Methionine transport in normal and cystic fibrosis fibroblasts

Initial rate kinetics of methionine transport, time course of accumulation of methionine, and efflux of accumulated methionine were studied in three normal and four CF human diploid fibroblast strains. The range of apparent Km's was 12.7-32.1 micrometer for the CF strains and 18.3-39.2 micrometer for the normal strains. The range of apparent Vmax's was 6.69-9.22 nmole mg-1 min-1 for the CF strains and 5.59-7.87 nmole mg-1 min-1 for the normal strains. The patterns of accumulation and efflux are quite similar in all the strains studied except for WI-38, which showed somewhat higher efflux and lower accumulation than for others. There was no significant difference in the kinetic parameters of methionine transport between CF and normal skin fibroblasts, and methionine transport will not serve as a marker for cystic fibrosis in cultured fibroblasts.

Membrane function in cystic fibrosis. I. Putrescine transport in normal and cystic fibrosis fibroblasts

Putrescine transport was examined in normal and cystic fibrosis fibroblasts. No differences were observed in accumulation pattern, kinetics of uptake, or efflux between CF and normal cells. In both growing and growth-arrested CF and normal fibroblasts, exogenously supplied putrescine remained unchanged for at least 60 min. Some differences were observed in the response of CF and normal cells to environmental (media) changes.