The TNF-family cytokine TL1A promotes allergic immunopathology through group 2 innate lymphoid cells.

The tumor necrosis factor (TNF)-family cytokine TL1A (TNFSF15) costimulates T cells and promotes diverse T cell-dependent models of autoimmune disease through its receptor DR3. TL1A polymorphisms also confer susceptibility to inflammatory bowel disease. Here, we find that allergic pathology driven by constitutive TL1A expression depends on interleukin-13 (IL-13), but not on T, NKT, mast cells, or commensal intestinal flora. Group 2 innate lymphoid cells (ILC2) express surface DR3 and produce IL-13 and other type 2 cytokines in response to TL1A. DR3 is required for ILC2 expansion and function in the setting of T cell-dependent and -independent models of allergic disease. By contrast, DR3-deficient ILC2 can still differentiate, expand, and produce IL-13 when stimulated by IL-25 or IL-33, and mediate expulsion of intestinal helminths. These data identify costimulation of ILC2 as a novel function of TL1A important for allergic lung disease, and suggest that TL1A may be a therapeutic target in these settings.

Reciprocal expression of IL-25 and IL-17A is important for allergic airways hyperreactivity.

BACKGROUND: Interleukin (IL)-25 (IL-17E) is a potent inducer of the type-2 immune effector response. Previously we have demonstrated that a neutralizing anti-IL-25 antibody, given during the establishment of ovalbumin-specific lung allergy, abrogates airways hyperreactivity. OBJECTIVE: Blocking IL-25 results in the suppression of IL-13, a cytokine known to exacerbate pulmonary inflammation, and an unexpected reciprocal increase in IL-17A. The role of IL-17A in asthma is complex with reports of both pro-inflammatory and anti-inflammatory functions. Our aim was to determine the influence of IL-17A in regulating IL-25-dependent lung allergy. METHOD: Neutralizing antibodies to IL-25 and/or IL-17A were administered during an experimental model of allergic asthma. Bronchoalveolar cell infiltrates and lung cytokine production were determined to assess lung inflammation. Invasive plethysmography was undertaken to measure lung function. RESULTS: Neutralization of IL-25 correlated with a decrease in IL-13 levels and an increase in IL-17A production, and an accompanying prevention of airway hyperresponsiveness (AHR). Notably, the blocking of IL-17A reversed the protective effects of treating with anti-IL-25 antibodies, resulting in the re-expression of several facets of the lung inflammatory response, including IL-13 and eotaxin production, eosinophilia and AHR. Using mice over-expressing IL-13 we demonstrate that treatment of these mice with anti-IL-25 fails to suppress IL-13 levels and in turn IL-17A levels remain suppressed. CONCLUSIONS AND CLINICAL RELEVANCE: IL-13 is known to be an important inducer of lung inflammation, causing goblet cell hyperplasia and promoting airways hyperreactivity. Our data now demonstrate that IL-13 also plays an important role in the genesis of lung inflammation downstream of IL-25 by suppressing a protective IL-17A response. These findings also highlight the important reciprocal interplay of the IL-17 family members, IL-25 and IL-17A, in regulating allergic lung responses and suggest that the balance of IL-17A, together with IL-25, will be an important consideration in the treatment of allergic asthma.

Tim1 and Tim3 are not essential for experimental allergic asthma.

BACKGROUND: Initial studies suggested that polymorphisms in Tim1 and Tim3 contribute to the development of airway hyperreactivity (AHR) in an acute mouse model of asthma. This was also mirrored in human genetic studies where polymorphisms in Tim1 and Tim3 have been associated with atopic populations. OBJECTIVE: Further studies using anti-Tim1 or -Tim3 antibodies, or Tim fusion proteins, have also suggested that these molecules may function as regulators of type-1 and type-2 immunity. However, their role in the development of AHR and airway inflammation remains unclear. Given the proposed roles for Tim1 and Tim3 in type-1 and type-2 responses, we sought to determine whether these molecules were important in regulating antigen-driven lung allergy and inflammation. METHOD: We used Tim1- and Tim3-deficient mice and determined how the development of allergic lung inflammation was affected. RESULTS: AHR was induced normally in the absence of both Tim1 and Tim3, although Tim1-deficient mice did show a small but significant decrease in cell infiltration in the lung and blood eosinophilia. Although Tim3 was expressed on CD4(+) T cells in the allergic lung, Tim1 expression was restricted to CD86(+) B cells. CONCLUSIONS AND CLINICAL RELEVANCE: Thus, Tim1 and Tim3 are not essential for the induction of the type-2 response in lung allergy. This is contrary to what was proposed in a number of other studies using neutralizing and activating antibodies and questions the clinical relevance of Tim1 and Tim3 for novel allergy therapies.

Brain damage after neonatal tetanus in a rural Kenyan hospital.

OBJECTIVE: Neonatal tetanus (NNT) is an important cause of mortality in resource poor countries, particularly sub-Saharan Africa. There are no reports of the long-term outcome of children who survive NNT in African hospitals. DESIGN: In a retrospective study of children discharged from Kilifi District Hospital (KDH), Kenya with NNT, each child was linked with a comparative child (CC) in the community matched for age, sex and locality. PARTICIPANTS: A total of 123 patients were admitted with NNT between 1992 and 1996, of whom 68% died. Twenty-three (59%) of the 39 survivors were traced in the community, 10 had moved away, six had died. OUTCOME MEASURES: NNT survivors underwent a neurological and developmental examination and a questionnaire was administered to the parents about the behaviour of the child. A verbal autopsy was used to determine the cause of death in children who had died after discharge. RESULTS: The head circumference of NNT survivors was significantly smaller than that of CC (P=0.037); eight children had microcephaly compared with one CC (P=0.011). NNT survivors had more problems with hand-eye co-ordination tasks (P=0.035), a lower summated developmental score (P=0.023) and more mild neurological abnormalities (P=0.008) than CC. Parents of NNT survivors reported more behavioural problems (P=0.02) than parents of CC. CONCLUSIONS: Children who survive NNT have evidence of brain damage that manifests as microcephaly, mild neurological abnormalities, developmental impairment - particularly fine motor difficulties - and behaviour problems.

Nonpeptide renin inhibitors with good intraduodenal bioavailability and efficacy in dog.

The aim of this study was the discovery of nonpeptide renin inhibitors with much improved oral absorption, bioavailability, and efficacy, for use as antihypertensive agents. Our prior efforts led to the identification of A-74273 [1,R = 3-(4-morpholino)propyl], with a bioavailability of 26 +/- 10% [10 mg/kg intraduodenally (id), dog]. In vivo metabolism studies of A-74273 showed that the morpholino moiety underwent metabolic degradation. Computer modeling of A-74273 bound to renin indicated that the C-terminus was involved in a hydrogen-bonding network. New C-terminal groups were examined in two series of nonpeptides for effects on renin binding potency, lipophilicity (log P), and aqueous solubility. Those groups which possessed multiple hydrogen-bonding ability (3,5-diaminotriazole, cyanoguanidines, morpholino) provided particularly potent renin binding. Intraduodenal bioavailabilities of selected compounds, evaluated in rats, ferrets, and dogs, were higher for inhibitors with moderate solubility as well as moderate lipophilicity, in general. Although the absolute values varied substantially among species, the relative ordering of the inhibitors in terms of absorption and bioavailability was reasonably consistent. Such well absorbed inhibitors (e.g. 41, 44, and 51) were demonstrated as highly efficacious hypotensive agents in the salt-depleted dog. We report here the discovery of a series of efficacious nonpeptide renin inhibitors based on the 3-azaglutaramide P2-P4 replacement, the best of which showed id bioavailabilities > 50% in dog.

Studies directed toward the design of orally active renin inhibitors. 2. Development of the efficacious, bioavailable renin inhibitor (2S)-2-benzyl-3- [[(1-methylpiperazin-4-yl)sulfonyl]propionyl]-3-thiazol-4-yl-L-alanine amide of (2S,3R,4S)-2-amino-1-cyclohexyl-3,4-dihydroxy-6-methylheptane (A-72517).

Employing a set of empirical guidelines for the design of well-absorbed renin inhibitors, we have followed two strategies to improve potency while maintaining bioavailability. One process involved incorporation of an extended N-terminal residue bearing a weakly basic substituent and is exemplified by compound 25. The other approach centered on the inclusion of an N-terminal sulfonamide and culminated in the discovery of inhibitor 32 (A-72517). Both 25 and 32 showed excellent bioavailability in the rat and ferret (> 25%) and, while subject to hepatic elimination in the monkey, were efficacious in this species.

Studies directed toward the design of orally active renin inhibitors. 1. Some factors influencing the absorption of small peptides.

A systematic evaluation of structure-absorption relationships using a high throughput intraduodenal rat screening model has led to the delineation of a set of structural parameters that appear to govern bioavailability in a series of peptide-based renin inhibitors. Optimum structures, exemplified by 25 and 41, incorporated a single, solubilizing substituent at the C- or N-terminus combined with a lipophilic P2-site residue. Both inhibitors gave unprecedented plasma drug levels upon intraduodenal administration to monkeys, and the calculated bioavailability for 41 (14 +/- 4%) is the highest reported for any peptidic renin inhibitor.

Effects of high doses of A-74273, a novel nonpeptidic and orally bioavailable renin inhibitor.

Previous studies with peptidic renin inhibitors have shown that high intravenous (i.v.) doses can induce unexpectedly large decreases in blood pressure (BP) that appear to be independent of plasma renin inhibition. A-74273 represents a new class of potent and orally bioavailable nonpeptidic renin inhibitors. We evaluated the BP effects of this renin inhibitor administered orally (p.o.) or i.v. at high doses to conscious salt-depleted dogs. Administration of A-74273 at 30 and 60 mg/kg p.o. (n = 6 per dose) produced similar maximum reductions in BP (-40 +/- 4 vs. -46 +/- 5 mm Hg) despite the occurrence of greater plasma drug concentrations at the higher dose. Duration of hypotension, however, was increased (p < 0.05) from 9 h at 30 mg/kg to 18 h at 60 mg/kg. The initial depressor response to 10 and 30 mg/kg i.v. doses of A-74273 (n = 6 per dose) was comparable, although duration and overall BP response was greater at 30 mg/kg i.v. No BP responses to A-74273 were noted in salt-replete dogs (n = 5). The hypotension produced by 30 mg/kg p.o. A-74273 was completely reversed by norepinephrine (NE 5 micrograms/kg/min; n = 5) or isotonic saline (4 ml/min/kg, n = 5) infusion. These studies demonstrate that high doses of A-74273 result in predictable BP responses that are renin-dependent and reversible. Therefore, large decreases in BP with high doses is not an attribute common to all renin inhibitors but appears to be a function of the structural characteristics specific to a particular compound.

C-terminal modifications of nonpeptide renin inhibitors: improved oral bioavailability via modification of physicochemical properties.

We describe the development of a series of soluble, potent, and bioavailable nonpeptide renin inhibitors. These inhibitors derived from a series of novel nonpeptide renin inhibitors which were recently identified in our laboratories, by alteration of the nature of the C-terminus (P2') of the molecules. Introduction of basic substituents into modified hydroxyethylene dipeptide isosteres gave inhibitors with improved solubility as well as improved potency against human plasma renin. In addition, these modifications produced inhibitors which displayed markedly improved intraduodenal bioavailability in both the ferret and cynomolgus monkey. We also present data which demonstrate excellent efficacy in the monkey for A-74273 (65), with an intraduodenal bioavailability of 16 +/- 4% in the monkey, compared to 1.7 +/- 0.5% for the dipeptide renin inhibitor enalkiren (A-64662, 75). A-74273 is an example of a nonpeptide inhibitor which possesses a good balance of the desirable properties of potency, solubility, and lipophilicity and which is well absorbed into the intestine.

Nonpeptide renin inhibitors employing a novel 3-aza(or oxa)-2,4-dialkyl glutaric acid moiety as a P2/P3 amide bond replacement.

A new series of renin inhibitors has been developed. The inhibitors feature a novel replacement for the P2/P3 dipeptide moiety normally associated with renin inhibitors. The dipeptide replacement was a (2S,4S)-3-aza(or oxa)-2,4-dialkylglutaric acid amide. Extensive structure-activity relationship studies determined that optimum potency was achieved when inhibitors employed a benzyl and butyl group at the C(4) and C(2) carbon position, respectively. In addition, maximum in vitro potency was obtained when the N-terminus was functionalized by incorporating a 4-(1,3-dioxabutyl)piperidine amide. SAR data suggested that the 1,3-dioxabutyl group (methoxymethyl ether) interacted by hydrogen bonding to groups in the S4 domain of renin. This hypothesis was strengthened when a 4-butylpiperidine amide was substituted and inhibitor potency decreased dramatically. Inhibitors employing this novel dipeptide mimic were prepared by coupling the glutaric acid amides with either the transition-state mimic (2S,3R,4S)-2-amino-1-cyclohexyl-3,4-dihydroxy-6- methylheptane (18) or the hydroxyethylene dipeptide isostere. The glutaric acid amides were prepared by two general procedures. The first procedure involved the reductive amination of alpha-amino acid esters with alpha-keto esters. The second procedure involved the displacement reaction of alpha-bromo esters or acids with alpha-amino acid amides.

A phase I study of hepatic arterial infusion using difluoromethylornithine.

Ten patients with metastatic disease to the liver were treated with difluoromethylornithine (DFMO) administered by continuous hepatic arterial infusion. Two of nine evaluable patients had an objective partial response. Stable disease was recorded in three patients. Ototoxicity was encountered in all patients who received a daily dose of DFMO equal to or greater than 1.0 g/m2.

Inhibition of polyamine biosynthesis by alpha-difluoromethylornithine in African trypanosomes and Pneumocystis carinii as a basis of chemotherapy: biochemical and clinical aspects.

The symposium provided dramatic evidence of the value of the use of polyamine inhibition via alpha-difluoromethylornithine (DFMO, eflornithine) for advances in chemotherapy of Trypanosoma brucei gambiense sleeping sickness and Pneumocystis carinii pneumonia in acquired immune deficiency syndrome (AIDS) and also for further understanding the metabolic importance of the ubiquitous polyamines in these organisms.

Terfenadine, safety and tolerance in controlled clinical trials.

alpha-[4-(1,1-Dimethylethyl)phenyl]-4-(hydroxydiphenylmethyl)-1- piperidinebutanol (terfenadine, RMI 9918, Triludan, Teldane, resp.) is a new histamine H1-receptor antagonist. In clinical trials, terfenadine has been studied extensively in adult patients and to a limited extent in children. Based on the results of the double-blind placebo controlled studies, the incidence of CNS depression (drowsiness, sleepiness, fatigue, weakness, lack of concentration, "fuzzy"/"blurred thinking") with doses of 120 mg/day or higher of terfenadine (12.6%) was similar to that of placebo (11.4%) while that of the comparative drugs such as chlorpheniramine (12 mg/day) or clemastine (2 mg/day) in these studies ranged from 22% to 26%. The incidences of all other side effects, including other CNS effects such as headache and stimulation with terfenadine and the other antihistamines were not different from those with placebo except for dryness of the nose, mouth or throat. Dryness was reported in a greater percentage of patients given clemastine (4.6%) or chlorpheniramine (4.5%) than in those given terfenadine (2.6%), d-chlorpheniramine (2.7%) or placebo (2.2%). It is concluded that the results of controlled clinical trials with terfenadine provide further evidence of the overall safety and lack of sedative effects of this drug.