The diurnal rhythm of the cytoprotective human trefoil protein TFF2 is reduced by factors associated with gastric mucosal damage: ageing, Helicobacter pylori infection, and sleep deprivation

OBJECTIVES: To determine if the normal TFF2 diurnal rhythm is disrupted in those with increased risk of gastric morbidity. Trefoil proteins protect the gastrointestinal mucosa from damage and aid its repair. TFF2 is considered the major cytoprotective gastric trefoil protein. There is a marked circadian variation in gastric luminal TFF2 in young healthy volunteers with peak levels present during the night. METHODS: Gastric juice was aspirated at two hourly intervals over a 24-h period via a nasogastric tube. TFF2 was measured by quantitative western transfer analysis. Helicobacter pylori (H. pylori) status was measured by C13 urea breath test and by serology. The effects of H. pylori infection, sleep deprivation, and ageing, which cause increased gastric morbidity, on the TFF2 circadian rhythm were tested. RESULTS: H. pylori infection attenuated the increase in TFF2 that occurs during the night. The TFF2 diurnal rhythm was reduced in older people and both the TFF2 level reached and the time at which the maximum TFF2 concentration occurs were associated inversely with age (p < 0.005). Sleep deprivation delayed the normal night time increase in gastric TFF2 and resulted in an overall reduction in TFF2 secretion. CONCLUSIONS: H. pylori infection, ageing, and sleep deprivation cause a reduction in the TFF2 diurnal rhythm. The demonstration that the TFF2 rhythm is impaired in cohorts of individuals known to suffer gastric symptoms suggests that interventions to restore the normal TFF2 rhythm in those with poor mucosal protection could reduce morbidity.     

Separation of on-target efficacy from adverse effects through rational design of a bitopic adenosine receptor agonist

The concepts of allosteric modulation and biased agonism are revolutionizing modern approaches to drug discovery, particularly in the field of G protein-coupled receptors (GPCRs). Both phenomena exploit topographically distinct binding sites to promote unique GPCR conformations that can lead to different patterns of cellular responsiveness. The adenosine A₁ GPCR (A₁AR) is a major therapeutic target for cardioprotection, but current agents acting on the receptor are clinically limited for this indication because of on-target bradycardia as a serious adverse effect. In the current study, we have rationally designed a novel A₁AR ligand (VCP746)—a hybrid molecule comprising adenosine linked to a positive allosteric modulator—specifically to engender biased signaling at the A₁AR. We validate that the interaction of VCP746 with the A₁AR is consistent with a bitopic mode of receptor engagement (i.e., concomitant association with orthosteric and allosteric sites) and that the compound displays biased agonism relative to prototypical A₁AR ligands. Importantly, we also show that the unique pharmacology of VCP746 is (patho)physiologically relevant, because the compound protects against ischemic insult in native A₁AR-expressing cardiomyoblasts and cardiomyocytes but does not affect rat atrial heart rate. Thus, this study provides proof of concept that bitopic ligands can be designed as biased agonists to promote on-target efficacy without on-target side effects.G protein-coupled receptors (GPCRs) are the largest family of cell surface proteins and tractable drug targets (1, 2). Unfortunately, there remains a high attrition rate associated with traditional GPCR-based drug discovery that, in part, reflects an emphasis on the endogenous agonist binding (orthosteric) site as the predominant means of achieving selective GPCR drug targeting (3). Over the last decade, substantial breakthroughs have occurred in the exploitation of topographically distinct GPCR allosteric sites as a means for attaining greater selectivity, especially in those instances where there is high sequence similarity in the orthosteric site across GPCR subtypes (4–6). However, there are increasing examples where both the therapeutic effect and adverse effects are mediated by the same GPCR target (7). In these situations, the desired selectivity needs to be attained at the level of the intracellular signaling pathways linked to a given receptor subtype.GPCRs are highly dynamic proteins, fluctuating between different conformations; these conformations can be linked to different cellular outcomes (8). Thus, chemically distinct ligands, interacting with either orthosteric or allosteric sites, have the potential to stabilize different interaction networks within a GPCR to promote a subset of signaling pathways linked to the receptor at the expense of others. This phenomenon has been termed biased agonism (7, 9, 10). The overall promise of biased agonism is the ability to design GPCR ligands that selectively engage therapeutically relevant signaling pathways while sparing pathways that contribute to undesirable side effects mediated by the same target.The adenosine receptor (AR) family is an important class of physiologically and therapeutically relevant GPCRs that can benefit substantially from more selective drug targeting. Although all four AR subtypes are expressed in the mammalian heart (11, 12), the well-known protective effects of adenosine in this tissue are predominantly mediated by the adenosine A₁ receptor (A₁AR) subtype, especially under conditions of ischemia and reperfusion injury (13–17). Unfortunately, the transition of A₁AR agonists into the clinic has been severely hindered because of high doses causing on-target bradycardia, atrioventricular block, and hypotension (13, 18). As a consequence, clinical trials of AR agonists have had limited success because of the suboptimal dose of agonist that can be used (19–22). It is possible that this problem may be overcome through the exploitation of biased agonism at the A₁AR.Although no study has identified biased orthosteric A₁AR ligands, we recently showed that the 2-amino-3-benzoylthiophene allosteric modulator (VCP171) could promote biased signaling in the activity of the prototypical orthosteric agonist, R(-)N6-(2-phenylisopropyl) adenosine (R-PIA) (23). Thus, we hypothesized that the rational design of a bitopic ligand (i.e., a class of hybrid molecule containing both orthosteric and allosteric pharmacophores) (24–26) may be able to achieve high efficacy and biased agonism at the A₁AR in a single molecule. Herein, we report proof of concept that it is possible to use this approach as a means to dissociate on-target efficacy from on-target side effects.     

Ablation of nonneoplastic Barrett's mucosa using argon plasma coagulation with concomitant esomeprazole therapy (APBANEX): a prospective multicenter evaluation

BACKGROUND: Complete reversal of Barrett's epithelium (BE) achieved by treatment with argon plasma coagulation (APC) is variable. The aim of this prospective study was to evaluate the effectiveness of high-power APC in a multicenter trial. METHODS: In seven study centers, 60 patients (mean age 57, range 27-77) with nonneoplastic BE (length 1-8 cm) were recruited for treatment with high-power APC (90 W) in combination with esomeprazole 80 mg/day. Video endoscopy, chromoendoscopy, and four-quadrant biopsies (4QB) were carried out during baseline endoscopy and regular intervals. The effect of ablation was classified as complete remission (CR), partial remission, or minor response. RESULTS: Fifty-one of the 60 patients completed ablation therapy. Three patients were lost to follow-up (FU). After a mean of 2.6 APC sessions (range 1-5) and a mean FU of 14 months (range 12-32), CR was achieved in 37 of 48 patients (77%). Major complications occurred in five of 51 patients (9.8%). CONCLUSIONS: Complete ablation of BE can be achieved in a high percentage of patients even in a multicenter design using high-power APC. However, APC has a relevant morbidity. Therefore, ablation of nonneoplastic BE cannot be recommended generally because incidence of cancer in BE is low.     

Epidemiology of FASD in a province in Italy: Prevalence and characteristics of children in a random sample of schools

BACKGROUND: Accurate estimates of the prevalence and characteristics of fetal alcohol syndrome (FAS) and fetal alcohol spectrum disorders (FASD) in a Western European population are lacking and are of particular interest in settings where the usual pattern of alcohol consumption is thought to be daily drinking with meals. To address these issues, an epidemiology study of FAS and other FASD was undertaken in Italian schools. METHODS: Primary schools (n = 25) in 2 health districts of the Lazio region were randomly selected and recruited for the study. Five hundred forty-three children, 50% of those enrolled in first-grade classes, received parental permission to participate in a 2-tiered, active case ascertainment screening process. Detailed evaluation of children selected in a preliminary screening phase was carried out on those who were small for height, weight, and head circumference and/or referred by teachers for suspected learning and behavioral problems. Detailed evaluation was carried out on each child's: (1) physical growth and dysmorphology, (2) psychological development and behavior, and (3) prenatal exposure to alcohol and other risk factors for FASD via maternal interviews. A group of 67 randomly selected children without FASD from the same classes was utilized as a comparison group. RESULTS: Using 2 denominators for prevalence estimation, a conservative one and a strict sample-based estimate, the prevalence of FAS in this province of Italy was 3.7 to 7.4 per 1,000 children. When cases of partial FAS (PFAS) and a case of alcohol-related neurodevelopmental deficits (ARND) were added to FAS cases, the rate of FASD was 20.3 to 40.5 per 1,000 and estimated at 35 per 1,000 overall or between 2.3 and 4.1% of all children. This exceeds previously published estimates of both FAS and FASD for the western world. Detailed data are presented that demonstrate the utility of the guidelines of the revised Institute of Medicine diagnostic criteria for FASD. Children with FASD are significantly more impaired/affected (p < 0.05) than randomly selected comparison children on all measures of growth deficiency, key facial features of FASD, overall dysmorphology scores, language comprehension, nonverbal IQ, and behavior. Maternal reports of current drinking were significantly higher for mothers of FASD children than comparison mothers, but reported rates of overall drinking during pregnancy were not significantly different. In contrast to expectations, daily drinking among mothers of the comparison group was not common. However, dysmorphology scores of the children were significantly correlated with drinking in the second and third trimesters, drinks per current drinking day, and current drinks per month. Finally, children with the physical features of FASD had lower IQs; nonverbal IQ was significantly correlated with head circumference and negatively correlated with overall dysmorphology score, smooth philtrum, and several other facial and physical anomalies characteristic of FAS. CONCLUSIONS: Using careful measures of ascertainment in a primary school setting, these results provide relatively high estimates of the prevalence of FASD and raise the question of whether FASD is more common in the western world than previously estimated.     

Laparoscopic Nissen fundoplication using laparosonic coagulating shears: report of a case

A 64-year-old man was admitted to Gunma University Hospital because of gastroesophageal reflux disease and hiatus hernia. Endoscopic examination showed a linear ulcer and mucosal redness in the lower esophagus. Gastrointestinal contrast study revealed a large esophageal hiatal sliding hernia. Laparoscopic Nissen fundoplication was then performed. Short gastric vessels were divided and lesser omentum was ablated with laparosonic coagulating shears, and the fundus of the stomach was used to construct the wrap around the esophagus. Three hundred and sixty degree fundoplication was undertaken using four sutures to secure the wrap. The patient is well and is currently free from reflux symptoms. Laparoscopic Nissen fundoplication is effective in the control of gastroesophageal reflux in the patient with hiatus hernia. This case report demonstrates that the use of laparosonic coagulating shears is effective for the division of the short gastric vessels.     

Familial-skewed X-chromosome inactivation as a predisposing factor for late-onset X-linked sideroblastic anemia in carrier females

X-linked sideroblastic anemia (XLSA) is caused by mutations in the erythroid-specific 5-aminolevulinic acid synthase (ALAS2) gene. An elderly woman who presented with an acquired sideroblastic anemia is studied. Molecular analysis revealed that she was heterozygous for a missense mutation in the ALAS2 gene, but she expressed only the mutated gene in reticulocytes. Her 2 daughters and a granddaughter were heterozygous for this mutation, had normal hemoglobin levels, and expressed the normal ALAS2 gene in reticulocytes. A grandson with a previous diagnosis of thalassemia intermedia was found to be hemizygous for the ALAS2 mutation. Treatment with pyridoxine completely corrected the anemia both in the proband and her grandson. All women who were analyzed in this family showed skewed X-chromosome inactivation in leukocytes, which indicated a hereditary condition associated with unbalanced lyonization. Because the preferentially active X chromosome carried the mutant ALAS2 allele, acquired skewing in the elderly likely worsened the genetic condition and abolished the normal ALAS2 allele expression in the proband. (Blood. 2000;96:4363-4365)     

Predictors for functional decline among nondisabled older Japanese living in a community during a 3-year follow-up

OBJECTIVES: To examine predictors for functional decline in basic activities of daily living (BADL) as well as predictors for decline in instrumental activities of daily living (IADL) among nondisabled older Japanese people living in a community during a 3-year interval from 1992 to 1995. DESIGN: A prospective cohort study. SETTING: A community-based environment. PARTICIPANTS: A total of 583 men and women aged 65 to 89 at baseline who were independent in both BADL and IADL. MEASUREMENTS: Independent variables regarding various factors potentially associated with functional decline were obtained from an interview survey and medical examinations at baseline. Dependent variables were functional status in BADL and IADL obtained at the time of the 3-year follow-up. RESULTS: During the 3-year follow-up, significant predictors for functional decline in BADL and only IADL decline included (1) age of > or = 75, (2) less hand-grip strength, and (3) a history of hospitalization during the past 1 year. In addition, having poor intellectual activities and having poor social roles were identified as significant predictors for functional decline in only IADL during the 3-year follow-up. Furthermore, not having the habit of taking a walk was identified as a significant predictor of functional decline in BADL during the 3-year interval. CONCLUSION: Having a high level hand-grip strength, good intellectual activities, and good social roles are strongly associated with remaining independence in IADL for the nondisabled Japanese persons aged > or = 65.     

How does measurement of platelet P-selectin compare with other methods of measuring platelet function as a means of determining the effectiveness of antiplatelet therapy?

Measurement of P-selectin on activated platelets as a means of measuring platelet function utilizing the technology described here has the advantage of not requiring immediate access to specialist equipment and expertise. Blood samples are activated, fixed, stored, and transported to a central laboratory for flow cytometric analysis. Here we have compared P-selectin with other more traditional approaches to measuring platelet function in blood and/or platelet-rich plasma (PRP) from patients with acute coronary syndromes on treatment for at least 1 month with either aspirin and clopidogrel or aspirin with prasugrel. The comparators were light transmission aggregometry (LTA), VerifyNow and Multiplate aggregometry (for determining the effects of aspirin) and LTA, VerifyNow and Multiplate together with the BioCytex VASP phosphorylation assay (for the P2Y₁₂ antagonists). The P-selectin Aspirin Test revealed substantial inhibition of platelet function in all but three of 96 patients receiving aspirin with clopidogrel and in none of 51 patients receiving aspirin and prasugrel. The results were very similar to those obtained using LTA. There was only one patient with high residual platelet aggregation and low P-selectin expression. The same patients identified as “non-responders” to aspirin also presented with the highest residual platelet activity as measured using the VerifyNow system, although not quite as well separated from the other values. With the Multiplate test only one of these patients clearly stood out from the others. The results obtained using the P-selectin P2Y₁₂ Test in 102 patients taking aspirin and clopidogrel were similar to the more traditional approaches in that a wide scatter of results was obtained. Generally, high values seen with the P-selectin P2Y₁₂ Test were also high with the LTA, VerifyNow, Multiplate, and BioCytex VASP P2Y₁₂ Tests. Similarly, low residual platelet function using the P2Y₁₂ test was seen irrespective of the testing procedure used. However, there were differences in some patients. Prasugrel was always more effective than clopidogrel in inhibiting platelet function with none of 56 patients (P-selectin and VerifyNow), only 2 of 56 patients (Multiplate) and only 3 of 56 patients (Biocytex VASP) demonstrating high on-treatment residual platelet reactivity (HRPR) defined using previously published cut-off values. The exception was LTA where there were 11 of 56 patients with HRPR. It remains to be seen which experimental approach provides the most useful information regarding outcomes after adjusting therapies in treated patients.     

Current Smoking and Prognosis After Acute ST-Segment Elevation Myocardial Infarction: New Pathophysiological Insights

ObjectivesThe aim of this study was to mechanistically investigate associations among cigarette smoking, microvascular pathology, and longer term health outcomes in patients with acute ST-segment elevation myocardial infarction (MI).BackgroundThe pathophysiology of myocardial reperfusion injury and prognosis in smokers with acute ST-segment elevation MI is incompletely understood.MethodsPatients were prospectively enrolled during emergency percutaneous coronary intervention. Microvascular function in the culprit artery was measured invasively. Contrast-enhanced magnetic resonance imaging (1.5-T) was performed 2 days and 6 months post-MI. Infarct size and microvascular obstruction were assessed using late gadolinium enhancement imaging. Myocardial hemorrhage was assessed with T2* mapping. Pre-specified endpoints included: 1) all-cause death or first heart failure hospitalization; and 2) cardiac death, nonfatal MI, or urgent coronary revascularization (major adverse cardiovascular events). Binary logistic regression (odds ratio [OR] with 95% confidence interval [CI]) with smoking status was used.ResultsIn total, 324 patients with ST-segment elevation MI were enrolled (mean age 59 years, 73% men, 60% current smokers). Current smokers were younger (age 55 ± 11 years vs. 65 ± 10 years, p < 0.001), with fewer patients with hypertension (52 ± 27% vs. 53 ± 41%, p = 0.007). Smokers had better TIMI (Thrombolysis In Myocardial Infarction) flow grade (≥2 vs. ≤1, p = 0.024) and ST-segment resolution (none vs. partial vs. complete, p = 0.010) post–percutaneous coronary intervention. On day 1, smokers had higher circulating C-reactive protein, neutrophil, and monocyte levels. Two days post-MI, smoking independently predicted infarct zone hemorrhage (OR: 2.76; 95% CI: 1.42 to 5.37; p = 0.003). After a median follow-up period of 4 years, smoking independently predicted all-cause death or heart failure events (OR: 2.20; 95% CI: 1.07 to 4.54) and major adverse cardiovascular events (OR: 2.79; 95% CI: 2.30 to 5.99).ConclusionsSmoking is associated with enhanced inflammation acutely, infarct-zone hemorrhage subsequently, and longer term adverse cardiac outcomes. Inflammation and irreversible myocardial hemorrhage post-MI represent mechanistic drivers for adverse long-term prognosis in smokers. (Detection and Significance of Heart Injury in ST Elevation Myocardial Infarction. [BHF MR-MI]; NCT02072850)