Extension of ustekinumab maintenance dosing interval in moderate-to-severe psoriasis: results of a phase IIIb, randomized, double-blinded, active-controlled, multicentre study (PSTELLAR).

BACKGROUND: Phase III studies showed that some patients maintained response for ≥ 6 months following ustekinumab discontinuation. OBJECTIVES: To assess clinical responses with extended ustekinumab maintenance dosing intervals. METHODS: Adults with moderate-to-severe plaque psoriasis received ustekinumab at weeks 0, 4 and 16 during open-label treatment. Patients achieving a week-28 Physician's Global Assessment (PGA) score of cleared/minimal (PGA = 0/1) were randomized 1 : 4 to group 1 [approved every 12 weeks (q12 wk) maintenance] or group 2 (q12-24 wk; response-based dosing determined by time to loss of PGA = 0/1). Key end points included the number of visits with PGA = 0/1 (primary end point) and ≥ 75% improvement in Psoriasis Area and Severity Index (PASI 75) between weeks 88 and 112, and PGA/PASI responses between weeks 28 and 112. RESULTS: Overall, 378 patients achieved PGA = 0/1 at week 28 and were randomized to group 1 (n = 76) or group 2 (n = 302). Patients in group 1 had numerically greater mean numbers of visits with PGA = 0/1 than group 2 and also with PASI 75 from week 88 to 112. A higher proportion of patients in group 1 (55%) than group 2 (39%) had PGA = 0/1 at all seven visits from week 88 to 112. Maintenance of response was observed with dose-interval extension beyond q12 wk in a subset of patients. Extending the dosing interval did not affect antibody development or safety. CONCLUSIONS: Efficacy was better maintained among week-28 PGA responders randomized to continue q12 wk ustekinumab vs. extending maintenance dosing based on clinical response, although some patients maintained high levels of efficacy with up to q24 wk dosing.

Quantitative MRI analysis of craniofacial bone marrow in patients with sickle cell disease.

BACKGROUND AND PURPOSE: Assessment of bone marrow is most commonly performed qualitatively in the spine or other large long bones. The craniofacial bones are less ideal for bone marrow analysis because of the relatively small bone marrow volume. Because patients with SCD often undergo repeated brain imaging to evaluate for cerebral vaso-occlusive disease, quantitative assessment of craniofacial bone marrow is a reasonable possibility in these patients. The purpose of this study was to investigate specific sickle cell disease changes in craniofacial bone marrow quantitatively by analyzing T1, T2, and secular-T2 relaxation times and volume with the use of quantitative MRI. MATERIALS AND METHODS: Fourteen patients with SCD and 17 control subjects were imaged with the mixed TSE pulse sequence at 1.5T. The craniofacial bones were manually segmented by using 3D Slicer to generate bone marrow volumes and to provide T1, T2, and secular-T2 relaxation times. RESULTS: All subjects exhibited a bimodal T1 histogram. In the SCD group, there was a decrease in amplitude in the first T1 peak and an increase in amplitude in the second T1 peak. The first T1 peak showed a significant increase in relaxation time compared with control subjects (P < .0001), whereas there was no significant difference in the second T1 peak. T2 and secular-T2 relaxation times were significantly shorter in the SCD group (T2, P < .0001; secular-T2, P < .0001). Increasing numbers of blood transfusions resulted in a decrease in T2 and secular-T2 times. Patients with SCD exhibited a larger bone marrow volume compared with control subjects, even after standardization. CONCLUSIONS: Patients with SCD exhibited significant quantifiable changes in the craniofacial bone marrow because of failure of red-to-yellow marrow conversion and iron deposition that can be identified by qMRI relaxometry and volumetry. Both qMRI relaxometry and volumetry may be used as noninvasive tools for assessment of disease severity.

Persistence of Mycobacterium tuberculosis in macrophages and mice requires the glyoxylate shunt enzyme isocitrate lyase.

Mycobacterium tuberculosis claims more human lives each year than any other bacterial pathogen. Infection is maintained in spite of acquired immunity and resists eradication by antimicrobials. Despite an urgent need for new therapies targeting persistent bacteria, our knowledge of bacterial metabolism throughout the course of infection remains rudimentary. Here we report that persistence of M. tuberculosis in mice is facilitated by isocitrate lyase (ICL), an enzyme essential for the metabolism of fatty acids. Disruption of the icl gene attenuated bacterial persistence and virulence in immune-competent mice without affecting bacterial growth during the acute phase of infection. A link between the requirement for ICL and the immune status of the host was established by the restored virulence of delta icl bacteria in interferon-gamma knockout mice. This link was apparent at the level of the infected macrophage: Activation of infected macrophages increased expression of ICL, and the delta icl mutant was markedly attenuated for survival in activated but not resting macrophages. These data suggest that the metabolism of M. tuberculosis in vivo is profoundly influenced by the host response to infection, an observation with important implications for the treatment of chronic tuberculosis.

Functional characterization of the MODY1 gene mutations HNF4(R127W), HNF4(V255M), and HNF4(E276Q).

Genetic studies have shown that mutations in the gene encoding hepatocyte nuclear factor (HNF)-4alpha, a member of the steroid/thyroid hormone receptor superfamily, give rise to early-onset type 2 diabetes (MODY1). The functional properties of mutant HNF-4alpha proteins and the molecular mechanisms by which they impair insulin secretion are largely unknown. In the present study, we have investigated transcriptional activation, DNA binding properties, and protein dimerization activity of three HNF-4alpha missense mutations--HNF4(R127W), HNF4(V255M), and HNF4(E276Q)--that have been associated with type 2 diabetes. We demonstrate that HNF4(E276Q) has lost its ability to bind to HNF-4 consensus binding sites and activate transcription. HNF4(E276Q) had no effect on the functional activity of wild-type HNF-4alpha in the pancreatic beta-cell line HIT-T15, but it exhibited weak dominant-negative activity in other cell types. Analysis of HNF4(E276Q) protein showed that it exists in two forms: a full length 54-kDa protein and a 40-kDa COOH-terminal protein lacking the NH2-terminal transactivation domain and the DNA binding domain. Immunoprecipitation experiments indicate that this truncated protein can bind to wild-type HNF-4alpha and may be responsible for the weak dominant-negative effects seen in these cells. In addition, we show that the transcriptional transactivation of HNF4(R127W) and HNF4(V255M) is indistinguishable from that of wild-type HNF-4alpha, suggesting that they are sequence polymorphisms. Our results demonstrate that HNF4(E276Q) is a loss-of-function mutation and that it identifies glutamic acid 276 in alpha-helix 8 of the ligand-binding domain of HNF-4alpha protein as a critical residue for DNA binding, transcriptional activation, and protein stability in vivo.

VIP and PACAP inhibit IL-12 production in LPS-stimulated macrophages. Subsequent effect on IFNgamma synthesis by T cells.

Since IL-12 plays a central role against intracellular pathogens, and contributes to the pathogenesis of immune diseases, its regulation is essential. This study examines the effect of two neuropeptides, vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase activating polypeptide (PACAP), on interleukin-12 (IL-12) production. VIP/PACAP inhibit IL-12 dose-dependently. Type 1 VIP receptor (VPAC1), and to a lesser degree type 2 VIP receptor (VPAC2), mediate the inhibition of IL-12, primarily through the cAMP/PKA pathway. VIP/PACAP inhibit the production of IL-12, IL-6, tumor necrosis factor alpha (TNFalpha), and interferon gamma (IFNgamma) in vivo in endotoxemic mice. The presence of VIP/PACAP in the lymphoid organs and the specific effects on cytokine production offer a physiological basis for their immunomodulatory role in vivo.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide prevent inducible nitric oxide synthase transcription in macrophages by inhibiting NF-kappa B and IFN regulatory factor 1 activation.

High-output nitric oxide (NO) production from activated macrophages, resulting from the induction of inducible NO synthase (iNOS) expression, represents a major mechanism for macrophage cytotoxicity against pathogens. However, despite its beneficial role in host defense, sustained high-output NO production was also implicated in a variety of acute inflammatory diseases and autoimmune diseases. Therefore, the down-regulation of iNOS expression during an inflammatory process plays a significant physiological role. This study examines the role of two immunomodulatory neuropeptides, the vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptide (PACAP), on NO production by LPS-, IFN-gamma-, and LPS/IFN-gamma-stimulated peritoneal macrophages and the Raw 264.7 cell line. Both VIP and PACAP inhibit NO production in a dose- and time-dependent manner by reducing iNOS expression at protein and mRNA level. VPAC1, the type 1 VIP receptor, which is constitutively expressed in macrophages, and to a lesser degree VPAC2, the type 2 VIP receptor, which is induced upon macrophage activation, mediate the effect of VIP/PACAP. VIP/PACAP inhibit iNOS expression and activity both in vivo and in vitro. Two transduction pathways appear to be involved, a cAMP-dependent pathway that preferentially inhibits IFN regulatory factor-1 transactivation and a cAMP-independent pathway that blocks NF-kappa B binding to the iNOS promoter. The down-regulation of iNOS expression, together with previously reported inhibitory effects on the production of the proinflammatory cytokines IL-6, TNF-alpha, and IL-12, and the stimulation of the anti-inflammatory IL-10, define VIP and PACAP as "macrophage deactivating factors" with significant physiological relevance.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide enhance IL-10 production by murine macrophages: in vitro and in vivo studies.

Vasoactive intestinal peptide (VIP), a neuropeptide present in the lymphoid microenvironment, and the structurally related pituitary adenylate cyclase-activating polypeptide (PACAP) act as potent anti-inflammatory agents that inhibit the function of activated macrophages and TH cells. Previous reports showed that VIP/PACAP inhibit IL-6 and TNF-alpha production in LPS-stimulated macrophages. The present study reports on the effect of VIP/PACAP on IL-10 production. Although VIP/PACAP do not induce IL-10 by themselves, they enhance IL-10 production in LPS-stimulated macrophages. The specific VPAC1 receptor mediates the stimulatory effect of VIP/PACAP, and cAMP is the major second messenger involved. VIP/PACAP increase IL-10 mRNA in LPS-stimulated cells, and the effect of transcriptional and protein synthesis inhibitors indicates de novo IL-10 production. Electromobility shift assays show that VIP/PACAP induce an increase in nuclear cAMP response element (CRE)-binding complexes, with CRE binding protein as the major active component. Treatments with either a VPAC1 antagonist or a protein kinase A inhibitor abolish IL-10 stimulation and, concomitantly, the increase in CRE binding. Effects similar to the in vitro stimulation of IL-10 were obtained in vivo in mice treated with LPS and VIP or PACAP. The neuropeptides induce increased levels of IL-10 in both serum and peritoneal fluid, and increased expression of the IL-10 mRNA in peritoneal exudate cells. The stimulation of IL-10 production in activated macrophages represents a novel anti-inflammatory activity of VIP and PACAP, which presumably acts in vivo in conjunction with the inhibition of proinflammatory cytokines such as IL-6 and TNF-alpha to reduce the magnitude of the immune response.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit tumor necrosis factor alpha transcriptional activation by regulating nuclear factor-kB and cAMP response element-binding protein/c-Jun.

Tumor necrosis factor alpha (TNFalpha), an early cytokine produced by activated macrophages, plays an essential role in normal and pathological inflammatory reactions. The excessive production of TNFalpha is prevented by the so-called "macrophage-deactivating factors." This study examines the role of two structurally related neuropeptides, the vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating peptide (PACAP), as inhibitors of TNFalpha. Both VIP and PACAP inhibit TNFalpha production from lipopolysaccharide-stimulated RAW 246.7 cells in a dose- and time-dependent manner. Although the activated cells express mRNA for all three VIP/PACAP receptors, agonist and antagonist studies indicate that the major receptor involved is VIP1R. VIP/PACAP inhibit TNFalpha gene expression by affecting both NF-kB binding and the composition of the cAMP responsive element binding complex (CREB/c-Jun). Two transduction pathways, a cAMP-dependent and a cAMP-independent pathway, are involved in the inhibition of TNFalpha gene expression and appear to differentially regulate the transcriptional factors involved. Because TNFalpha plays a central role in various inflammatory diseases such as endotoxic shock, multiple sclerosis, cerebral malaria, and various autoimmune conditions, the down-regulatory effect of VIP/PACAP may have a significant therapeutic potential.