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Biomedical subjects

L Adorini

Publications and source records attributed to L Adorini.

At least 19 recordsLinked to original sources
PubMed2005

Colon cancer and solar ultraviolet B radiation and prevention and treatment of colon cancer in mice with vitamin D and its Gemini analogs.

It has been recognized that people who live at higher latitudes and who are vitamin D deficient are at higher risk of dying from many common cancers including colon cancer. To evaluate the role of vitamin D deficiency on colon tumor growth, Balb/c adult male mice were fed either a vitamin D sufficient or vitamin D deficient diet for 10 weeks. Mice were arranged into groups of six and each animal received subcutaneously 10(4) MC-26 cells in the posterior trunk. The tumor size was recorded daily. By day 9 there was a significant difference in tumor volume between the vitamin D sufficient and vitamin D deficient mice. By day 18 the vitamin D deficient animals had a tumor size that was 56% larger compared to the animals that were vitamin D sufficient. To determine whether treatment with active vitamin D analogs could further decrease colon tumor growth in a vitamin D sufficient state, groups of mice were treated with the novel 19-nor-Gemini compounds. The mice were fed a low calcium diet. Twenty-four hours after tumor implantation, the mice received, three times weekly, one of the vitamin D analogs or the vehicle. The group that received Gemini 1,25-dihydroxy-21(3-hydroxy-3-trifluoromethyl-4-trifluoro-butynyl)-19-nor-20S-cholecalciferol (3) showed a dose-dependent decrease in tumor volume. On day 19, at the dose level of 0.02microg molar equivalents (E), the tumor volume was reduced by 41% when compared to the control group. At the same time point, the hexadeuterated analog 1,25-dihydroxy-21(3-hydroxy-3-trifluoromethyl-4-trifluoro-butynyl)-26,27-hexadeutero-19-nor-20S-cholecalciferol (4), administered at the 10-fold lower dose of 0.002microgE, showed a 52% reduction in tumor volume (p<0.05), compared to the control group. Animals that received 1,25(OH)(2)D(3) at 0.002 and 0.02microg showed a trend in tumor volume reduction at the highest dose but the changes were not statistically significant. An evaluation of serum calcium concentrations revealed that the calcium levels were normal in all groups, except the group receiving 0.02microgE of 4. The results from these studies demonstrate that vitamin D deficiency may accelerate colon cancer growth and that novel Gemini analogs of 1,25(OH)(2)D(3) may be an effective new approach for colon cancer treatment.

Animals↗
PubMed2005

Manipulating dendritic cells to induce regulatory T cells.

Dendritic cells (DCs) induce and regulate T-cell responses, and tolerogenic DCs can promote the development of regulatory T cells with suppressive activity. The possibility of manipulating DCs using different pharmacological or biological agents, enabling them to exert tolerogenic activities, could be exploited to better control a variety of chronic inflammatory conditions, from autoimmune diseases to allograft rejection.

Animals↗
PubMed2004

Inhibition of prostate cell growth by BXL-628, a calcitriol analogue selected for a phase II clinical trial in patients with benign prostate hyperplasia.

OBJECTIVE: Calcitriol analogues might represent an interesting new therapy for benign prostate hyperplasia (BPH). We here report the preclinical characterization of BXL-628, an analogue selected for an ongoing double-blind, randomized, placebo-controlled phase II trial in BPH. DESIGN: Experiments with BXL-628 were carried out in human BPH cells and in the ventral prostate of intact and castrated rats. METHODS: BPH cell and rat prostate growth were evaluated along with morphological and biochemical hallmarks of apoptosis. RESULTS: BXL-628 inhibited human BPH cell proliferation and induced apoptosis even in the presence of androgens or growth factors. It also decreased prostate growth to an extent similar to finasteride, inducing DNA fragmentation and apoptosis, both in intact and in testosterone-supplemented castrated rats. Accordingly, BXL-628, like finasteride, increased the expression of clusterin, a prostatic atrophy marker. However, BXL-628 did not inhibit 5 alpha-reductase 1 and 2, did not bind to the androgen receptor (AR) in BPH homogenates and did not affect AR-coupled luciferase activity. In addition, BXL-628 did not affect rat pituitary and testis activity or calcemia. CONCLUSIONS: BXL-628 inhibited in vitro and in vivo prostate cell proliferation, and therefore might represent a novel, interesting option for the treatment of BPH.

Animals↗
PubMed2003

Inhibition of spontaneous and androgen-induced prostate growth by a nonhypercalcemic calcitriol analog.

We have recently found that analog V (BXL-353, a calcitriol analog) inhibits growth factor (GF)-stimulated human benign prostate hyperplasia (BPH) cell proliferation by disrupting signal transduction, reducing Bcl-2 expression, and inducing apoptosis. We now report that BXL-353 blocks in vitro and in vivo testosterone (T) activity. BPH cells responded to T and dihydrotestosterone (DHT) with dose-dependent growth and reduced apoptosis. Exposure of BPH cells to BXL-353 significantly antagonized both T- and DHT-induced proliferation and induced apoptosis, even in the presence of T. To verify whether BXL-353 reduced prostate growth in vivo, we administered it orally to either intact or castrated rats, supplemented with T enanthate. Nonhypercalcemic doses of BXL-353 time- and dose-dependently reduced the androgen effect on ventral prostate weight, similarly to finasteride. Comparable results were obtained after chronic administration of BXL-353 to intact rats. Clusterin (an atrophy marker) gene and protein were up-regulated by BXL-353 in rat prostate, and nuclear fragmentation was widely present. The antiandrogenic properties of BXL-353 did not interfere with pituitary and testis function, as assessed by serum determination of rat LH and T. BXL-353 did not compete for androgen binding to BPH homogenates and failed to inhibit 5alpha-reductase type 1 and type 2 activities. In conclusion, BXL-353 blocks in vitro and in vivo androgen-stimulated prostate cell growth, probably acting downstream from the androgen receptor, without affecting calcemia or sex hormone secretion. BXL-353 and other vitamin D(3) analogs might thus represent an interesting class of compounds for treating patients with BPH.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2002

Des (1-3) IGF-I-stimulated growth of human stromal BPH cells is inhibited by a vitamin D3 analogue.

Prostate growth and differentiation is under the control of androgens not only during fetal life and childhood but also in adulthood, and it has been proposed that increased prostatic concentration of androgens, or increased androgen responsiveness, causes benign prostatic hyperplasia (BPH). However, different androgen ablation strategies such as treatment with GnRH agonists and finasteride resulted in a modest decrease of the hyperplastic prostate volume. In the last few years it became evident that both androgen-dependent and androgen-independent growth factors promote prostate enlargement by inducing cell proliferation or reducing apoptosis. Therefore, new therapeutic strategies, aimed at reducing intraprostatic growth factor signaling, are under investigation. In this study, we report further evidence that a non hypercalcemic-analogue of vitamin D(3), analogue (V) decreases growth factor-induced human BPH cell proliferation and survival. We found that Des (1-3) insulin-like growth factor [Des (1-3) IGF-I], an IGF-I analogue, which does not bind to IGF-binding proteins, is a potent mitogen for BPH stromal cells via a dual mechanism: stimulation of cell growth and inhibition of apoptosis. Similar results were previously reported for another growth factor for BPH cells, keratinocyte growth factor (KGF). Accordingly, we speculate that both KGF and IGF might be involved in the pathogenesis of BPH. We also found analogue (V) not only inhibits the mitogenic activity of growth factors on BPH cells, but even decreased the basal expression of bcl-2, and induced apoptosis. Therefore, vitamin D(3) analogues might be considered for the medical treatment of BPH.

Animals↗
PubMed2002

Secretory defects induced by immunosuppressive agents on human pancreatic beta-cells.

Despite the considerable interest for islet and pancreas transplantation, remarkably little is known about the direct effects of immunosuppressive drugs on human beta-cell function. We measured different insulin secretory parameters and insulin gene expression of human islets cultured for 5 days in the presence of mycophenolate mofetil (MMF), cyclosporin A (CsA), tacrolimus (FK506) or a mixture of 3 cytokines. Basal insulin release after exposure to cytokines and FK506 was significantly higher than in control islets. Responsiveness to an acute glucose stimulus did not differ significantly between control and treated islets. However, absolute incremental insulin responses (delta-AUCs) of islets exposed to cytokines or FK506 were significantly higher compared to islets exposed to CsA or MMF, mainly because of the higher basal release. Indeed, maximal over basal release (stimulation index, SI) tended to be lower in islets exposed to FK506 than in control islets. Insulin gene expression was significantly reduced only in islets exposed to CsA. FK506 was, among those tested, the immunosuppressive drug that most profoundly altered the normal insulin secretory pattern of human beta-cells, whereas CsA was the only inhibiting insulin gene expression. Although the abnormalities induced by the immunosoppressive drugs utilized in this study were modest, these in vitro data are consistent with the reported in vivo diabetogenicity of CsA and FK506 and point to MMF as the ideal immunosuppressive agent from a pancreatic beta-cell point of view.

Adult↗
PubMed2002

Polymorphisms in the Il12b gene affect structure and expression of IL-12 in NOD and other autoimmune-prone mouse strains.

Interleukin (Il)-12 is a heterodimeric cytokine composed of 35 and 40 kD chains that plays a key role in the induction of Th1 cells, a T cell subset involved in many autoimmune diseases. We report here the cDNA sequence encoding the IL-12 p40 subunit from the autoimmune-prone non-obese diabetic (NOD) mouse, which spontaneously develops type 1 diabetes. Compared with the C57BL/6 sequence, there are two base changes that lead to amino acid replacements. Other autoimmune-prone strains, but not the diabetes-resistant NOR strain, share the same allele as NOD. We found both trans- and cis- allele-dependent effects on levels of basal and induced IL-12p40 expression. Furthermore, we show that one of these changes results in a structural change in the p40 molecule, as evidenced by the failure of a monoclonal antibody to bind NOD IL-12. These findings have implications for the predisposition to autoimmune responses in NOD and other autoimmune-prone mouse strains.

Animals↗
PubMed2001

IL-12 administration reveals diabetogenic T cells in genetically resistant I-Ealpha-transgenic nonobese diabetic mice: resistance to autoimmune diabetes is associated with binding of Ealpha-derived peptides to the I-A(g7) molecule.

Nonobese diabetic (NOD) and NOD-DRalpha transgenic (tg) mice, expressing Aalpha(d):Abeta(g7) and Aalpha(d):Abeta(g7) plus DRalpha:Ebeta(g7) class II molecules, respectively, both develop insulin-dependent diabetes mellitus (IDDM), whereas NOD-Ealpha tg mice expressing Aalpha(d):Abeta(g7) plus Ealpha:Ebeta(g7) are protected. We show that IL-12 administration induces rapid IDDM onset in NOD-DRalpha but fails to provoke insulitis and diabetes in NOD-Ealpha tg mice. Nevertheless, T cells from IL-12-treated NOD-Ealpha tg mice secrete IFN-gamma and transfer IDDM to NOD-SCID and NOD-Ealpha-SCID recipients, demonstrating the presence of peripheral diabetogenic Th1 cells in the protected mice. Surprisingly, regulatory cells were undetectable. Moreover, Ealpha:Ebeta(g7) could substitute for DRalpha:Ebeta(g7) in Ag presentation, arguing against mechanisms of protection involving capture of diabetogenic I-A(g7)-restricted epitopes by Ealpha:Ebeta(g7)molecules. Interestingly, the expression of naturally processed epitopes derived from DRalpha- and Ealpha-chains bound to I-A(g7) is different in the two strains of tg mice, and the difference is enhanced by IL-12 administration. I-A(g7) molecules from both NOD-DRalpha and NOD-Ealpha tg mice present the conserved DRalpha/Ealpha 52-68 sequence, at high and low levels, respectively. In addition, only IDDM-resistant NOD-Ealpha tg mice possess APCs bearing Ealpha65-77/I-A(g7) complexes, which tolerize the specific T cells. This is associated with the selective inhibition of the response to insulinoma-associated protein 2 (IA-2), an autoantigen in IDDM. Our results support protective mechanisms based on I-A(g7) blockade by peptides unique to the Ealpha-chain, such as Ealpha65-77 and/or tolerance of diabetogenic T cells cross-reactive with Ealpha-peptide/I-A(g7) complexes.

Animals↗
PubMed2001

Cardiomyocytes induce endothelial cells to trans-differentiate into cardiac muscle: implications for myocardium regeneration.

The concept of tissue-restricted differentiation of postnatal stem cells has been challenged by recent evidence showing pluripotency for hematopoietic, mesenchymal, and neural stem cells. Furthermore, rare but well documented examples exist of already differentiated cells in developing mammals that change fate and trans-differentiate into another cell type. Here, we report that endothelial cells, either freshly isolated from embryonic vessels or established as homogeneous cells in culture, differentiate into beating cardiomyocytes and express cardiac markers when cocultured with neonatal rat cardiomyocytes or when injected into postischemic adult mouse heart. Human umbilical vein endothelial cells also differentiate into cardiomyocytes under similar experimental conditions and transiently coexpress von Willebrand factor and sarcomeric myosin. In contrast, neural stem cells, which efficiently differentiate into skeletal muscle, differentiate into cardiomyocytes at a low rate. Fibroblast growth factor 2 and bone morphogenetic protein 4, which activate cardiac differentiation in embryonic cells, do not activate cardiogenesis in endothelial cells or stimulate trans-differentiation in coculture, suggesting that different signaling molecules are responsible for cardiac induction during embryogenesis and in successive periods of development. The fact that endothelial cells can generate cardiomyocytes sheds additional light on the plasticity of endothelial cells during development and opens perspectives for cell autologous replacement therapies.

Animals↗
PubMed2001

Cutting edge: selective usage of chemokine receptors by plasmacytoid dendritic cells.

The existence of dendritic cell (DC) subsets is firmly established, but their trafficking properties are virtually unknown. In this study, we show that myeloid (M-DCs) and plasmacytoid (P-DCs) DCs isolated from human blood differ widely in the capacity to migrate to chemotactic stimuli. The pattern of chemokine receptors expressed by blood M-DCs and P-DCs, with the exception of CCR7, is similar. However, most chemokine receptors of P-DCs, in particular those specific for inflammatory chemokines and classical chemotactic agonists, are not functional in circulating cells. Following maturation induced by CD40 ligation, the receptors for inflammatory chemokines are down-regulated, and CCR7 on P-DCs becomes coupled to migration. The drastically impaired capacity of blood P-DCs to migrate in response to inflammatory chemotactic signals contrasts with the response to lymph node-homing chemokines, indicating a propensity to migrate to secondary lymphoid organs rather than to sites of inflammation.

Cell Differentiation↗
PubMed2001

Regulatory T cells induced by 1 alpha,25-dihydroxyvitamin D3 and mycophenolate mofetil treatment mediate transplantation tolerance.

1alpha,25-dihydroxyvitamin D3, the active form of vitamin D3, and mycophenolate mofetil, a selective inhibitor of T and B cell proliferation, modulate APC function and induce dendritic cells (DCs) with a tolerogenic phenotype. Here we show that a short treatment with these agents induces tolerance to fully mismatched mouse islet allografts that is stable to challenge with donor-type spleen cells and allows acceptance of donor-type vascularized heart grafts. Peritransplant macrophages and DCs from tolerant mice express down-regulated CD40, CD80, and CD86 costimulatory molecules. In addition, DCs from the graft area of tolerant mice secrete, upon stimulation with CD4+ cells, 10-fold lower levels of IL-12 compared with DCs from acutely rejecting mice, and induce a CD4+ T cell response characterized by selective abrogation of IFN-gamma production. CD4+ but not CD8+ or class II+ cells from tolerant mice, transferred into naive syngeneic recipients, prevent rejection of donor-type islet grafts. Graft acceptance is associated with impaired development of IFN-gamma-producing type 1 CD4+ and CD8+ cells and an increased percentage of CD4+CD25+ regulatory cells expressing CD152 in the spleen and in the transplant-draining lymph node. Transfer of CD4+CD25+ cells from tolerant but not naive mice protects 100% of the syngeneic recipients from islet allograft rejection. These results demonstrate that a short treatment with immunosuppressive agents, such as 1alpha,25-dihydroxyvitamin D3/mycophenolate mofetil, induces tolerance to islet allografts associated with an increased frequency of CD4+CD25+ regulatory cells that can adoptively transfer transplantation tolerance.

Administration, Oral↗
PubMed2001

Intrathecal delivery of IFN-gamma protects C57BL/6 mice from chronic-progressive experimental autoimmune encephalomyelitis by increasing apoptosis of central nervous system-infiltrating lymphocytes.

The exclusive detrimental role of proinflammatory cytokines in demyelinating diseases of the CNS, such as multiple sclerosis, is controversial. Here we show that the intrathecal delivery of an HSV-1-derived vector engineered with the mouse IFN-gamma gene leads to persistent (up to 4 wk) CNS production of IFN-gamma and inhibits the course of a chronic-progressive form of experimental autoimmune encephalomyelitis (EAE) induced in C57BL/6 mice by myelin oligodendrocyte glycoprotein (MOG)(35-55). Mice treated with the IFN-gamma-containing vector before EAE onset showed an earlier onset but a milder course of the disease compared with control mice treated with the empty vector. In addition, 83% of IFN-gamma-treated mice completely recovered within 25 days post immunization, whereas control mice did not recover up to 60 days post immunization. Mice treated with the IFN-gamma-containing vector within 1 wk after EAE onset partially recovered from the disease within 25 days after vector injection, whereas control mice worsened. Recovery from EAE in mice treated with IFN-gamma was associated with a significant increase of CNS-infiltrating lymphocytes undergoing apoptosis. During the recovery phase, the mRNA level of TNFR1 was also significantly increased in CNS-infiltrating cells from IFN-gamma-treated mice compared with controls. Our results further challenge the exclusive detrimental role of IFN-gamma in the CNS during EAE/multiple sclerosis, and indicate that CNS-confined inflammation may induce protective immunological countermechanisms leading to a faster clearance of encephalitogenic T cells by apoptosis, thus restoring the immune privilege of the CNS.

Animals↗
PubMed2001

The frequency of high avidity T cells determines the hierarchy of determinant spreading.

Autoimmunity often spreads in a predefined pattern during the progression of T cell-mediated autoimmune diseases. This progression has been well described in animal models and in man, but the basis for this phenomenon is little understood. To gain insight into the factors that determine this spreading hierarchy, we characterized the binding affinity of a panel of beta cell-autoantigenic peptides to I-Ag7, as well as the precursor frequency, functional avidity, and phenotype of the T cells that recognize these peptides in type 1 diabetes-prone nonobese diabetic mice. We observed that autoimmunity gradually spreads from a beta cell determinant, which had the largest precursor pool of high avidity T cells, to beta cell determinants with progressively smaller and lower avidity T cell precursor pools. This correlation between the sequential development of spontaneous T cell autoimmunity and the frequency and avidity of autoantigen-reactive T cells suggests that the extent to which T cells were negatively selected by the self-determinants is the key factor determining the spreading hierarchy.

Amino Acid Sequence↗
PubMed2001

Delivery to the central nervous system of a nonreplicative herpes simplex type 1 vector engineered with the interleukin 4 gene protects rhesus monkeys from hyperacute autoimmune encephalomyelitis.

Systemic administration of antiinflammatory molecules to patients affected by immune-mediated inflammatory demyelinating diseases of the central nervous system (CNS) has limited therapeutic efficacy due to the presence of the blood-brain barrier (BBB). We found that three of five rhesus monkeys injected intrathecally with a replication-defective herpes simplex virus (HSV) type 1-derived vector engineered with the human interleukin 4 (IL-4) gene were protected from an hyperacute and lethal form of experimental autoimmune encephalomyelitis induced by whole myelin. The intrathecally injected vector consistently diffused within the CNS via the cerebrospinal fluid and infected ependymal cells, which in turn sustained in situ production of IL-4 without overt immunological or toxic side effects. In EAE-protected monkeys, IL-4-gene therapy significantly decreased the number of brain as well as spinal cord inflammatory perivenular infiltrates and the extent of demyelination, necrosis, and axonal loss. The protective effect was associated with in situ downregulation of inflammatory mediators such as tumor necrosis factor alpha (TNF-alpha) and monocyte chemoattractant protein 1 (MCP-1), upregulation of transforming growth factor beta (TGF-beta), and preservation of BBB integrity. Our results indicate that intrathecal delivery of HSV-1-derived vectors containing antiinflammatory cytokine genes may play a major role in the future therapeutic armamentarium of inflammatory CNS-confined demyelinating diseases and, in particular, in the most fulminant forms where conventional therapeutic approaches have, so far, failed to achieve a satisfactory control of the disease evolution.

Animals↗
PubMed2001

The ependymal route to the CNS: an emerging gene-therapy approach for MS.

The systemic administration of anti-inflammatory molecules to patients affected by immune-mediated inflammatory demyelinating diseases of the central nervous system (CNS), such as multiple sclerosis, has limited therapeutic efficacy owing to the presence of the blood-brain barrier. The delivery of drugs to the CNS using a nonreplicative viral vector engineered with genes encoding anti-inflammatory cytokines might represent an alternative therapeutic strategy. Here, we propose accessing the CNS through the ependymal-leptomeningeal route. This approach is based on the injection of nonreplicative vectors into the cerebrospinal fluid space. These vectors are able to infect the ependymal and leptomeningeal cells consistently and without side effects, and in turn, produce the 'therapeutic' product of the transgene in the CNS for extended periods of time. This strategy could represent an alternative treatment for inflammatory neurological disorders when systemic immunosuppressive therapies fail to control the evolution of disease satisfactorily.

Blood-Brain Barrier↗