Structure-Based Design of Xanthine-Imidazopyridines and -Imidazothiazoles as Highly Potent and In Vivo Efficacious Tryptophan Hydroxylase Inhibitors.

Tryptophan hydroxylases catalyze the first and rate-limiting step in the biosynthesis of serotonin, a well-known neurotransmitter that plays an important role in multiple physiological functions. A reduction of serotonin levels, especially in the brain, can cause dysregulation leading to depression or insomnia. In contrast, overproduction of peripheral serotonin is associated with symptoms like carcinoid syndrome and pulmonary arterial hypertension. Recently, we developed a class of TPH inhibitors based on xanthine-benzimidazoles, characterized by a tripartite-binding mode spanning the binding sites of the cosubstrate pterin and the substrate tryptophan and by chelation of the catalytic iron ion. Herein, we describe the structure-based development of a second generation of xanthine-imidiazopyridines and -imidazothiazoles designed to inhibit TPH1 in the periphery while preventing the interaction with TPH2 in the brain. Lead compound 32 (TPT-004) shows superior pharmacokinetic and pharmacodynamic properties as well as efficacy in preclinical models of peripheral serotonin attenuation and colorectal tumor growth.

Delayed renal injury in survivors of hematologic acute radiation syndrome.

PURPOSE: A mass casualty disaster involving radiological or nuclear agents continues to be a public health concern which requires consideration of both acute and late tissue toxicities in exposed victims. With the advent of advanced treatment options for the mitigation of hematological injuries, there are likely to be survivors of total body irradiation (TBI) exposures as high as 8-10 Gy. These survivors are at risk for a range of delayed multi-organ morbidities including progressive renal failure. MATERIAL AND METHODS: Here, we established the WAG/RijCmcr rat as an effective model for the evaluation of medical countermeasures (MCM) for acute hematologic radiation syndrome (H-ARS). The LD50/30 dose for adult and pediatric WAG/RijCmcr rats was determined for both sexes. We then confirmed the FDA-approved MCM pegfilgrastim (peg-GCSF, Neulasta®) mitigates H-ARS in adult male and female rats. Finally, we evaluated survival and renal dysfunction up to 300 d post-TBI in male and female adult rats. RESULTS: In the WAG/RijCmcr rat model, 87.5% and 100% of adult rats succumb to lethal hematopoietic acute radiation syndrome (H-ARS) at TBI doses of 8 and 8.5 Gy, respectively. A single dose of the hematopoietic growth factor peg-GCSF administered at 24 h post-TBI improved survival during H-ARS. Peg-GCSF treatment improved 30 d survival from 12.5% to 83% at 8 Gy and from 0% to 63% at 8.5 Gy. We then followed survivors of H-ARS through day 300. Rats exposed to TBI doses greater than 8 Gy had a 26% reduction in survival over days 30-300 compared to rats exposed to 7.75 Gy TBI. Concurrent with the reduction in long-term survival, a dose-dependent impairment of renal function as assessed by blood urea nitrogen (BUN) and urine protein to urine creatinine ratio (UP:UC) was observed. CONCLUSION: Together, these data show survivors of H-ARS are at risk for the development of delayed renal toxicity and emphasize the need for the development of medical countermeasures for delayed renal injury.

Four Genes Predictive for the Severity of Hematological Damage Reveal a Similar Response after X Irradiation and Chemotherapy.

Radiological and especially nuclear accidents and incidents pose a threat to populations. In such events, gene expression (GE) analysis of a set of 4 genes (FDXR, DDB2, POU2AF1, WNT3) is an emerging approach for early and high-throughput prediction of the later manifesting severity degrees of the hematological acute radiation syndrome (H-ARS). Validation of this gene set on radiation victims is difficult since these events are rare. However, chemotherapy (CTX) is widely used e.g., breast cancer patient treatment and pathomechanisms, as well as blood cell count changes are comparable among both exposure types. We wondered whether GE changes are similarly deregulated after CTX, which would be interpreted as a confirmation of our already identified gene set for H-ARS prediction after irradiation. We examined radiation-induced differential GE (DGE) of our gene set as a positive control using in vitro whole blood samples from ten healthy donors (6 females, 4 males, aged: 24-40 years). Blood was incubated in vitro for 8 h after X irradiation with 0 and 4 Gy (1 Gy/min). These data were compared with DGE measured in vivo in blood samples of 10 breast tumor CTX patients (10 females, aged: 39-71 years) before and 4 days after administration of cyclophosphamide and epirubicin. RNA was isolated, reverse transcribed and quantitative real-time polymerase-chain-reaction (qRT-PCR) was performed to assess DGE of FDXR, DDB2, POU2AF1 and WNT3 relative to the unexposed samples using TaqMan assays. After X irradiation, we found a significant upregulation (irrespective of sex) with mean fold changes of 21 (P < 0.001) and 7 (P < 0.001) for FDXR and DDB2 and a significant down-regulation with mean fold changes of 2.5 (P < 0.001) and 2 (P = 0.005) for POU2AF1 and WNT3, respectively. After CTX, a similar pattern was observed, although mean fold changes of up-regulated FDXR (6-fold, P < 0.001) and DDB2 (3-fold, P < 0.001) as well as down-regulated POU2AF1 (1.2-fold, P = 0.270) and WNT3 (1.3-fold, P = 0.069) appeared lower corresponding to less altered blood cell count changes observed after CTX compared to historic radiation exposure data. However, a subpopulation of CTX patients (n = 6) showed on average a significant downregulation of POU2AF1 (1.8-fold, P = 0.04) and WNT3 (2.1-fold, P = 0.008). In summary, the pattern of up-regulated GE changes observed in all CTX patients and down-regulated GE changes observed in a subgroup of CTX patients appeared comparable with an already identified gene set predictive for the radiation-induced H-ARS. This underlines the significance of in vivo GE measurements in CTX patients, employed as a surrogate model to further validate already identified radiation-induced GE changes predictive for the H-ARS.

Structure-Based Design of Xanthine-Benzimidazole Derivatives as Novel and Potent Tryptophan Hydroxylase Inhibitors.

Tryptophan hydroxylases catalyze the first and rate-limiting step in the synthesis of serotonin. Serotonin is a key neurotransmitter in the central nervous system and, in the periphery, functions as a local hormone with multiple physiological functions. Studies in genetically altered mouse models have shown that dysregulation of peripheral serotonin levels leads to metabolic, inflammatory, and fibrotic diseases. Overproduction of serotonin by tumor cells causes severe symptoms typical for the carcinoid syndrome, and tryptophan hydroxylase inhibitors are already in clinical use for patients suffering from this disease. Here, we describe a novel class of potent tryptophan hydroxylase inhibitors, characterized by spanning all active binding sites important for catalysis, specifically those of the cosubstrate pterin, the substrate tryptophan as well as directly chelating the catalytic iron ion. The inhibitors were designed to efficiently reduce serotonin in the periphery while not passing the blood-brain barrier, thus preserving serotonin levels in the brain.

The 11-year long-term follow-up study from the randomized BENEFIT CIS trial.

OBJECTIVE: To assess outcomes for patients treated with interferon beta-1b immediately after clinically isolated syndrome (CIS) or after a short delay. METHODS: Participants in BENEFIT (Betaferon/Betaseron in Newly Emerging MS for Initial Treatment) were randomly assigned to receive interferon beta-1b (early treatment) or placebo (delayed treatment). After conversion to clinically definite multiple sclerosis (CDMS) or 2 years, patients on placebo could switch to interferon beta-1b or another treatment. Eleven years after randomization, patients were reassessed. RESULTS: Two hundred seventy-eight (59.4%) of the original 468 patients (71.3% of those eligible at participating sites) were enrolled (early: 167 [57.2%]; delayed: 111 [63.1%]). After 11 years, risk of CDMS remained lower in the early-treatment arm compared with the delayed-treatment arm (p = 0.0012), with longer time to first relapse (median [Q1, Q3] days: 1,888 [540, not reached] vs 931 [253, 3,296]; p = 0.0005) and lower overall annualized relapse rate (0.21 vs 0.26; p = 0.0018). Only 25 patients (5.9%, overall; early, 4.5%; delayed, 8.3%) converted to secondary progressive multiple sclerosis. Expanded Disability Status Scale scores remained low and stable, with no difference between treatment arms (median [Q1, Q3]: 2.0 [1.0, 3.0]). The early-treatment group had better Paced Auditory Serial Addition Task-3 total scores (p = 0.0070). Employment rates remained high, and health resource utilization tended to be low in both groups. MRI metrics did not differ between groups. CONCLUSIONS: Although the delay in treatment was relatively short, several clinical outcomes favored earlier treatment. Along with low rates of disability and disease progression in both groups, this supports the value of treatment at CIS. CLINICALTRIALSGOV IDENTIFIER: NCT01795872. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that early compared to delayed treatment prolongs time to CDMS in CIS after 11 years.

Analysis of Diagnoses Associated with Multiple Sclerosis-Related In-Hospital Mortality Using the Premier Hospital Database.

BACKGROUND: We sought to compare mortality rates and related diagnoses in hospitalized patients with multiple sclerosis (MS), those with diabetes mellitus (DM), and the general hospitalized population (GHP). METHODS: Patients who died between 2007 and 2011 were identified in the US hospital-based Premier Healthcare Database. Demographic information was collected, mortality rates calculated, and principal diagnoses categorized. RESULTS: Of 55,152 unique patients with MS identified, 1518 died. Mean age at death was 10 years younger for the MS group (63.4 years) than for the DM (73.3 years) and GHP (73.1 years) groups. Age-adjusted mortality rates, based on the 2000 US Standard Million Population, were 1077, 1248, and 1133 per 100,000, respectively. Infection was the most common principal diagnosis at the hospital stay during which the patient died in the MS cohort (43.1% vs. 26.3% and 24.0% in the DM and GHP groups, respectively). Other common principal diagnoses in the MS group included pulmonary (17.5%) and cardiovascular (12.1%) disease. Septicemia/sepsis/septic shock was a secondary diagnosis for 50.7% of patients with MS versus 36.0% and 31.0% of patients in the DM and GHP cohorts, respectively. CONCLUSIONS: Patients with MS had a shorter life span than patients with DM or the GHP and were more likely to have a principal diagnosis of infection at their final hospital stay. However, the database was limited to codes recorded in the hospital; diagnoses received outside the hospital were not captured.

Molecular mechanism underlying the impact of vitamin D on disease activity of MS.

OBJECTIVE: Some previous studies suggest modest to strong effects of 25-hydroxyvitamin D (25(OH)D) on multiple sclerosis (MS) activity. The objective of this study was to explore the mechanistic rationale that may explain potential clinical effects of 25(OH)D. METHODS: This study measured serum 25(OH)D levels and global gene expression profiles over a course of up to 2 years in patients starting treatment with interferon beta-1b (IFNB-1b) after a clinically isolated syndrome. MS disease activity was assessed by the number of gadolinium-enhancing lesions present on repeated magnetic resonance imaging (MRIs). RESULTS: The number of gadolinium-enhancing lesions was highly significantly associated with 25(OH)D levels. Conducting various systems-level analyses on the molecular level, multiple lines of evidence indicated that 25(OH)D regulates expression dynamics of a large gene-gene interaction system which primarily regulates immune modulatory processes modulating MS activity. The vitamin D response element was significantly enriched in this system, indicating a direct regulation of this gene interaction network through the vitamin D receptor. With increasing 25(OH)D levels, resulting regulation of this system was associated with a decrease in MS activity. Within the complex network of genes that are regulated by 25(OH)D, well-described targets of IFNB-1b and a regulator of sphingosine-1-phosphate bioavailability were found. The 25(OH)D effects on MS activity were additively enhanced by IFNB-1b. INTERPRETATION: Here, we provide mechanistic evidence that an unbalanced 25(OH)D gene expression system may affect MS activity. Our findings support a potential benefit of monitoring and managing vitamin D levels (e.g., through supplementation) in early MS patients treated with IFN-beta-1b.

Causes of death among commercially insured multiple sclerosis patients in the United States.

BACKGROUND: Information on causes of death (CODs) for patients with multiple sclerosis (MS) in the United States is sparse and limited by standard categorizations of underlying and immediate CODs on death certificates. Prior research indicated that excess mortality among MS patients was largely due to greater mortality from infectious, cardiovascular, or pulmonary causes. OBJECTIVE: To analyze disease categories in order to gain insight to pathways, which lead directly to death in MS patients. METHODS: Commercially insured MS patients enrolled in the OptumInsight Research database between 1996 and 2009 were matched to non-MS comparators on age/residence at index year and sex. The cause most-directly leading to death from the death certificate, referred to as the "principal" COD, was determined using an algorithm to minimize the selection of either MS or cardiac/pulmonary arrest as the COD. Principal CODs were categorized into MS, cancer, cardiovascular, infectious, suicide, accidental, pulmonary, other, or unknown. Infectious, cardiovascular, and pulmonary CODs were further subcategorized. RESULTS: 30,402 MS patients were matched to 89,818 controls, with mortality rates of 899 and 446 deaths/100,000 person-years, respectively. Excluding MS, differences in mortality rate between MS patients and non-MS comparators were largely attributable to infections, cardiovascular causes, and pulmonary problems. Of the 95 excessive deaths (per 100,000 person-years) related to infectious causes, 41 (43.2%) were due to pulmonary infections and 45 (47.4%) were attributed to sepsis. Of the 46 excessive deaths (per 100,000 person-years) related to pulmonary causes, 27 (58.7%) were due to aspiration. No single diagnostic entity predominated for the 60 excessive deaths (per 100,000 person-years) attributable to cardiac CODs. CONCLUSIONS: The principal COD algorithm improved on other methods of determining COD in MS patients from death certificates. A greater awareness of the common CODs in MS patients will allow physicians to anticipate potential problems and, thereby, improve the care that they provide.

Vitamin D as an early predictor of multiple sclerosis activity and progression.

IMPORTANCE: It remains unclear whether vitamin D insufficiency, which is common in individuals with multiple sclerosis (MS), has an adverse effect on MS outcomes. OBJECTIVES: To determine whether serum concentrations of 25-hydroxyvitamin D (25[OH]D), a marker of vitamin D status, predict disease activity and prognosis in patients with a first event suggestive of MS (clinically isolated syndrome). DESIGN, SETTING, AND PARTICIPANTS: The Betaferon/Betaseron in Newly Emerging multiple sclerosis For Initial Treatment study was a randomized trial originally designed to evaluate the impact of early vs delayed interferon beta-1b treatment in patients with clinically isolated syndrome. Serum 25(OH)D concentrations were measured at baseline and 6, 12, and 24 months. A total of 465 of the 468 patients randomized had at least 1 25(OH)D measurement, and 334 patients had them at both the 6- and 12-month (seasonally asynchronous) measurements. Patients were followed up for 5 years clinically and by magnetic resonance imaging. MAIN OUTCOMES AND MEASURES: New active lesions, increased T2 lesion volume, and brain volume on magnetic resonance imaging, as well as MS relapses and disability (Expanded Disability Status Scale score). RESULTS: Higher 25(OH)D levels predicted reduced MS activity and a slower rate of progression. A 50-nmol/L (20-ng/mL) increment in average serum 25(OH)D levels within the first 12 months predicted a 57% lower rate of new active lesions (P < .001), 57% lower relapse rate (P = .03), 25% lower yearly increase in T2 lesion volume (P < .001), and 0.41% lower yearly loss in brain volume (P = .07) from months 12 to 60. Similar associations were found between 25(OH)D measured up to 12 months and MS activity or progression from months 24 to 60. In analyses using dichotomous 25(OH)D levels, values greater than or equal to 50 nmol/L (20 ng/mL) at up to 12 months predicted lower disability (Expanded Disability Status Scale score, -0.17; P = .004) during the subsequent 4 years. CONCLUSIONS AND RELEVANCE: Among patients with MS mainly treated with interferon beta-1b, low 25(OH)D levels early in the disease course are a strong risk factor for long-term MS activity and progression.

Interferon beta-1b reduces black holes in a randomised trial of clinically isolated syndrome.

BACKGROUND: Multiple sclerosis (MS) is characterised by inflammatory lesions of the central nervous system. Interferon beta-1b (IFNB-1b) has been shown to improve clinical and magnetic resonance imaging (MRI) measures for patients with MS. OBJECTIVE: To evaluate whether IFNB-1b in patients presenting with clinically isolated syndromes (CIS) prevented persisting T1 hypointensities on MRI (persistent black holes (PBHs)). METHODS: In the placebo-controlled phase, patients (n = 468) were initially randomised to IFNB-1b (n = 292) or placebo (n = 176) for two years or clinically definite MS (CDMS). In the open-label phase (n = 418), both groups were offered IFNB-1b for up to five years. Lesions were classified as PBHs if T1 hypointensity persisted throughout the last available scan (minimum time one year). RESULTS: A total of 435 patients were evaluable for analysis. The number of PBHs/patient was lower in the early rather than the delayed treatment arm during both phases (.42 vs .71, p = .0102 and .70 vs 1.17, p = .0121). Exploratory analyses identified baseline characteristics that affected rate of conversion. CONCLUSIONS: Although the rate of lesions that converted to PBH showed no significant differences between groups, the numbers of PBHs per patient out of new lesions was significantly lower in IFNB-1b patients compared to patients on placebo. TRIAL REGISTRATION NUMBER: NCT00544037.

Long-term cost-effectiveness model of interferon beta-1b in the early treatment of multiple sclerosis in the United States.

BACKGROUND: Multiple sclerosis (MS) is a potentially debilitating autoimmune disease that affects the brain and spinal cord. Disease-modifying therapies have been shown to slow disease progression but were not believed to prolong the survival of patients with MS. The recent 21-Year Long-Term Follow-Up (21Y-LTF) study found a significant survival advantage for patients receiving early treatment with interferon beta (IFNß)-1b compared with placebo (no early treatment). OBJECTIVES: The aim of this study was to conduct cost-effectiveness analyses estimating the long-term benefit of early treatment with IFNß-1b among MS patients from a US societal perspective. METHODS: A Markov model was developed to simulate the experience of patients with MS from the 21Y-LTF study over a lifetime. Patients were randomized to receive either IFNß-1b or placebo for up to 5 years and then receive a variety of MS treatments (including no treatment) thereafter. Survival data reported from the 21Y-LTF study were incorporated into the model. The model assumes that patients' MS was managed in similar ways for both groups during the uncontrolled phase of the 21Y-LTF study (ie, survival difference between the 2 groups is the result of early use of IFNß-1b). Health outcomes were life-years and quality-adjusted life-years (QALYs). Costs included treatments, direct disease management, informal care, and lost productivities and were reported in 2011 US dollars. RESULTS: In the modeled placebo group, the median age at death was predicted to be 63.7 years, and the median survival time from disease onset was 36.7 years. Early treatment with IFNß-1b reduced the lost health benefits by 2.8 life-years and 1.9 QALYs, respectively, after discounting. Total discounted cost for IFNß-1b-treated patients was $86,223 higher than that of patients receiving placebo. The incremental cost-effectiveness ratio was $46,357 per QALY gained and $30,967 per life-year gained. Sensitivity analyses indicate the robustness of the model's results. CONCLUSIONS: Treatment with IFNß-1b during the earlier disease phase of patients with MS significantly increased patient life-years and QALYs. IFNß-1b is likely to be a cost-effective intervention for MS.

Effects of interferon beta-1b on cognitive performance in patients with a first event suggestive of multiple sclerosis.

BACKGROUND: Cognitive dysfunction occurs at the earliest stages of multiple sclerosis (MS), including the stage of clinically isolated syndrome (CIS). METHODS: We evaluated the impact of interferon beta-1b (IFNß-1b) 250 µg on cognitive performance during the CIS stage in the BENEFITstudy. Cognition was assessed by Paced Auditory Serial Addition Test-3" (PASAT-3") scores. RESULTS: Improvement in PASAT-3" score from baseline to year two was greater for IFNß-1b treatment than placebo in patients not reaching clinically definite MS (CDMS) by year two. The treatment effect was maintained at year five and was statistically significant. CONCLUSIONS: To conclude, early IFNß-1b treatment had a sustained positive effect on PASAT-3" score over the 5-year BENEFIT study.

Analysis and evaluation of environmental tobacco smoke exposure as a risk factor for chronic cough.

Exposure to environmental tobacco smoke (ETS) and active tobacco smoking has been shown to increase symptoms of bronchial asthma such as bronchoconstriction but effects on other respiratory symptoms remain poorly assessed. Current levels of exposure to tobacco smoke may also be responsible for the development of chronic cough in both children and adults. The present study analyses the effects of tobacco smoke exposure as potential causes of chronic cough. A panel of PubMed-based searches was performed relating the symptom of cough to various forms of tobacco smoke exposure. It was found that especially prenatal and postnatal exposures to ETS have an important influence on children's respiratory health including the symptom of cough. These effects may be prevented if children and pregnant women are protected from exposure to ETS. Whereas the total number of studies addressing the relationship between cough and ETS exposure is relatively small, the present study demonstrated that there is a critical amount of data pointing to a causative role of environmental ETS exposure for the respiratory symptom of cough. Since research efforts have only targeted this effect to a minor extent, future epidemiological and experimental studies are needed to further unravel the relation between ETS and cough.

Substance P mediates AP-1 induction in A549 cells via reactive oxygen species.

A common feature in asthma is the induction of reactive oxygen species (ROS) and the AP-1 transcription factor during the inflammatory process. AP-1 induction leads to an increased expression of pro-inflammatory cytokines. Also, higher levels of the pro-inflammatory neuropeptide substance P (SP) have been reported in bronchoalveolar-lavage fluid of asthmatics. Here, the role of SP on ROS induction and the downstream activation of AP-1 in A549 airway epithelial cells was investigated by dichloroflourescein-diacetate method and reporter gene assays. The SP-mediated AP-1 induction was dependent on extracellular calcium and ROS. The likely source of ROS are the mitochondria as rotenone inhibited AP-1 induction and the p47phox subunit of the NADPH oxidase complex, responsible for ROS generation in phagocytotic cells, was not expressed in A549 cells assayed by RT-PCR. This is consistent with results obtained from cells of murine bronchial epithelium, isolated by laser capture microdissection. In summary, this study provides evidence for an SP-mediated induction of AP-1, which may contribute to the expression of pro-inflammatory cytokines.